1% Building the JDK 2 3## TL;DR (Instructions for the Impatient) 4 5If you are eager to try out building the JDK, these simple steps works most of 6the time. They assume that you have installed Git (and Cygwin if running 7on Windows) and cloned the top-level JDK repository that you want to build. 8 9 1. [Get the complete source code](#getting-the-source-code): \ 10 `git clone https://git.openjdk.java.net/jdk/` 11 12 2. [Run configure](#running-configure): \ 13 `bash configure` 14 15 If `configure` fails due to missing dependencies (to either the 16 [toolchain](#native-compiler-toolchain-requirements), [build tools]( 17 #build-tools-requirements), [external libraries]( 18 #external-library-requirements) or the [boot JDK](#boot-jdk-requirements)), 19 most of the time it prints a suggestion on how to resolve the situation on 20 your platform. Follow the instructions, and try running `bash configure` 21 again. 22 23 3. [Run make](#running-make): \ 24 `make images` 25 26 4. Verify your newly built JDK: \ 27 `./build/*/images/jdk/bin/java -version` 28 29 5. [Run basic tests](##running-tests): \ 30 `make run-test-tier1` 31 32If any of these steps failed, or if you want to know more about build 33requirements or build functionality, please continue reading this document. 34 35## Introduction 36 37The JDK is a complex software project. Building it requires a certain amount of 38technical expertise, a fair number of dependencies on external software, and 39reasonably powerful hardware. 40 41If you just want to use the JDK and not build it yourself, this document is not 42for you. See for instance [OpenJDK installation]( 43http://openjdk.java.net/install) for some methods of installing a prebuilt 44JDK. 45 46## Getting the Source Code 47 48Make sure you are getting the correct version. As of JDK 10, the source is no 49longer split into separate repositories so you only need to clone one single 50repository. At the [OpenJDK Git site](https://git.openjdk.java.net/) you 51can see a list of all available repositories. If you want to build an older version, 52e.g. JDK 11, it is recommended that you get the `jdk11u` repo, which contains 53incremental updates, instead of the `jdk11` repo, which was frozen at JDK 11 GA. 54 55If you are new to Git, a good place to start is the book [Pro 56Git](https://git-scm.com/book/en/v2). The rest of this document 57assumes a working knowledge of Git. 58 59### Special Considerations 60 61For a smooth building experience, it is recommended that you follow these rules 62on where and how to check out the source code. 63 64 * Do not check out the source code in a path which contains spaces. Chances 65 are the build will not work. This is most likely to be an issue on Windows 66 systems. 67 68 * Do not check out the source code in a path which has a very long name or is 69 nested many levels deep. Chances are you will hit an OS limitation during 70 the build. 71 72 * Put the source code on a local disk, not a network share. If possible, use 73 an SSD. The build process is very disk intensive, and having slow disk 74 access will significantly increase build times. If you need to use a 75 network share for the source code, see below for suggestions on how to keep 76 the build artifacts on a local disk. 77 78 * On Windows, if using [Cygwin](#cygwin), extra care must be taken to make sure 79 the environment is consistent. It is recommended that you follow this 80 procedure: 81 82 * Create the directory that is going to contain the top directory of the 83 JDK clone by using the `mkdir` command in the Cygwin bash shell. 84 That is, do *not* create it using Windows Explorer. This will ensure 85 that it will have proper Cygwin attributes, and that it's children will 86 inherit those attributes. 87 88 * Do not put the JDK clone in a path under your Cygwin home 89 directory. This is especially important if your user name contains 90 spaces and/or mixed upper and lower case letters. 91 92 * You need to install a git client. You have two choices, Cygwin git or 93 Git for Windows. Unfortunately there are pros and cons with each choice. 94 95 * The Cygwin `git` client has no line ending issues and understands 96 Cygwin paths (which are used throughout the JDK build system). 97 However, it does not currently work well with the Skara CLI tooling. 98 Please see the [Skara wiki on Git clients]( 99 https://wiki.openjdk.java.net/display/SKARA/Skara#Skara-Git) for 100 up-to-date information about the Skara git client support. 101 102 * The [Git for Windows](https://gitforwindows.org) client has issues 103 with line endings, and do not understand Cygwin paths. It does work 104 well with the Skara CLI tooling, however. To alleviate the line ending 105 problems, make sure you set `core.autocrlf` to `false` (this is asked 106 during installation). 107 108 Failure to follow this procedure might result in hard-to-debug build 109 problems. 110 111## Build Hardware Requirements 112 113The JDK is a massive project, and require machines ranging from decent to 114powerful to be able to build in a reasonable amount of time, or to be able to 115complete a build at all. 116 117We *strongly* recommend usage of an SSD disk for the build, since disk speed is 118one of the limiting factors for build performance. 119 120### Building on x86 121 122At a minimum, a machine with 2-4 cores is advisable, as well as 2-4 GB of RAM. 123(The more cores to use, the more memory you need.) At least 6 GB of free disk 124space is required. 125 126Even for 32-bit builds, it is recommended to use a 64-bit build machine, and 127instead create a 32-bit target using `--with-target-bits=32`. 128 129### Building on aarch64 130 131At a minimum, a machine with 8 cores is advisable, as well as 8 GB of RAM. 132(The more cores to use, the more memory you need.) At least 6 GB of free disk 133space is required. 134 135If you do not have access to sufficiently powerful hardware, it is also 136possible to use [cross-compiling](#cross-compiling). 137 138### Building on 32-bit arm 139 140This is not recommended. Instead, see the section on [Cross-compiling]( 141#cross-compiling). 142 143## Operating System Requirements 144 145The mainline JDK project supports Linux, macOS, AIX and Windows. 146Support for other operating system, e.g. BSD, exists in separate "port" 147projects. 148 149In general, the JDK can be built on a wide range of versions of these operating 150systems, but the further you deviate from what is tested on a daily basis, the 151more likely you are to run into problems. 152 153This table lists the OS versions used by Oracle when building the JDK. Such 154information is always subject to change, but this table is up to date at the 155time of writing. 156 157 Operating system Vendor/version used 158 ----------------- ------------------------------------------------------- 159 Linux Oracle Enterprise Linux 6.4 / 7.6 160 macOS Mac OS X 10.13 (High Sierra) 161 Windows Windows Server 2012 R2 162 163The double version numbers for Linux are due to the hybrid model 164used at Oracle, where header files and external libraries from an older version 165are used when building on a more modern version of the OS. 166 167The Build Group has a wiki page with [Supported Build Platforms]( 168https://wiki.openjdk.java.net/display/Build/Supported+Build+Platforms). From 169time to time, this is updated by contributors to list successes or failures of 170building on different platforms. 171 172### Windows 173 174Windows XP is not a supported platform, but all newer Windows should be able to 175build the JDK. 176 177On Windows, it is important that you pay attention to the instructions in the 178[Special Considerations](#special-considerations). 179 180Windows is the only non-POSIX OS supported by the JDK, and as such, requires 181some extra care. A POSIX support layer is required to build on Windows. 182Currently, the only supported such layers are Cygwin and Windows Subsystem for 183Linux (WSL). (Msys is no longer supported due to a too old bash; msys2 would 184likely be possible to support in a future version but that would require effort 185to implement.) 186 187Internally in the build system, all paths are represented as Unix-style paths, 188e.g. `/cygdrive/c/git/jdk/Makefile` rather than `C:\git\jdk\Makefile`. This 189rule also applies to input to the build system, e.g. in arguments to 190`configure`. So, use `--with-msvcr-dll=/cygdrive/c/msvcr100.dll` rather than 191`--with-msvcr-dll=c:\msvcr100.dll`. For details on this conversion, see the section 192on [Fixpath](#fixpath). 193 194#### Cygwin 195 196A functioning [Cygwin](http://www.cygwin.com/) environment is required for 197building the JDK on Windows. If you have a 64-bit OS, we strongly recommend 198using the 64-bit version of Cygwin. 199 200**Note:** Cygwin has a model of continuously updating all packages without any 201easy way to install or revert to a specific version of a package. This means 202that whenever you add or update a package in Cygwin, you might (inadvertently) 203update tools that are used by the JDK build process, and that can cause 204unexpected build problems. 205 206The JDK requires GNU Make 4.0 or greater in Cygwin. This is usually not a 207problem, since Cygwin currently only distributes GNU Make at a version above 2084.0. 209 210Apart from the basic Cygwin installation, the following packages must also be 211installed: 212 213 * `autoconf` 214 * `make` 215 * `zip` 216 * `unzip` 217 218Often, you can install these packages using the following command line: 219``` 220<path to Cygwin setup>/setup-x86_64 -q -P autoconf -P make -P unzip -P zip 221``` 222 223Unfortunately, Cygwin can be unreliable in certain circumstances. If you 224experience build tool crashes or strange issues when building on Windows, 225please check the Cygwin FAQ on the ["BLODA" list]( 226https://cygwin.com/faq/faq.html#faq.using.bloda) and the section on [fork() 227failures](https://cygwin.com/faq/faq.html#faq.using.fixing-fork-failures). 228 229#### Windows Subsystem for Linux (WSL) 230 231Windows 10 1809 or newer is supported due to a dependency on the wslpath utility 232and support for environment variable sharing through WSLENV. Version 1803 can 233work but intermittent build failures have been observed. 234 235It's possible to build both Windows and Linux binaries from WSL. To build 236Windows binaries, you must use a Windows boot JDK (located in a 237Windows-accessible directory). To build Linux binaries, you must use a Linux 238boot JDK. The default behavior is to build for Windows. To build for Linux, pass 239`--build=x86_64-unknown-linux-gnu --host=x86_64-unknown-linux-gnu` to 240`configure`. 241 242If building Windows binaries, the source code must be located in a Windows- 243accessible directory. This is because Windows executables (such as Visual Studio 244and the boot JDK) must be able to access the source code. Also, the drive where 245the source is stored must be mounted as case-insensitive by changing either 246/etc/fstab or /etc/wsl.conf in WSL. Individual directories may be corrected 247using the fsutil tool in case the source was cloned before changing the mount 248options. 249 250Note that while it's possible to build on WSL, testing is still not fully 251supported. 252 253### macOS 254 255Apple is using a quite aggressive scheme of pushing OS updates, and coupling 256these updates with required updates of Xcode. Unfortunately, this makes it 257difficult for a project such as the JDK to keep pace with a continuously updated 258machine running macOS. See the section on [Apple Xcode](#apple-xcode) on some 259strategies to deal with this. 260 261It is recommended that you use at least Mac OS X 10.13 (High Sierra). At the time 262of writing, the JDK has been successfully compiled on macOS 10.12 (Sierra). 263 264The standard macOS environment contains the basic tooling needed to build, but 265for external libraries a package manager is recommended. The JDK uses 266[homebrew](https://brew.sh/) in the examples, but feel free to use whatever 267manager you want (or none). 268 269### Linux 270 271It is often not much problem to build the JDK on Linux. The only general advice 272is to try to use the compilers, external libraries and header files as provided 273by your distribution. 274 275The basic tooling is provided as part of the core operating system, but you 276will most likely need to install developer packages. 277 278For apt-based distributions (Debian, Ubuntu, etc), try this: 279``` 280sudo apt-get install build-essential 281``` 282 283For rpm-based distributions (Fedora, Red Hat, etc), try this: 284``` 285sudo yum groupinstall "Development Tools" 286``` 287 288### AIX 289 290Please consult the AIX section of the [Supported Build Platforms]( 291https://wiki.openjdk.java.net/display/Build/Supported+Build+Platforms) OpenJDK 292Build Wiki page for details about which versions of AIX are supported. 293 294## Native Compiler (Toolchain) Requirements 295 296Large portions of the JDK consists of native code, that needs to be compiled to 297be able to run on the target platform. In theory, toolchain and operating 298system should be independent factors, but in practice there's more or less a 299one-to-one correlation between target operating system and toolchain. 300 301 Operating system Supported toolchain 302 ------------------ ------------------------- 303 Linux gcc, clang 304 macOS Apple Xcode (using clang) 305 AIX IBM XL C/C++ 306 Windows Microsoft Visual Studio 307 308Please see the individual sections on the toolchains for version 309recommendations. As a reference, these versions of the toolchains are used, at 310the time of writing, by Oracle for the daily builds of the JDK. It should be 311possible to compile the JDK with both older and newer versions, but the closer 312you stay to this list, the more likely you are to compile successfully without 313issues. 314 315 Operating system Toolchain version 316 ------------------ ------------------------------------------------------- 317 Linux gcc 9.2.0 318 macOS Apple Xcode 10.1 (using clang 10.0.0) 319 Windows Microsoft Visual Studio 2019 update 16.5.3 320 321All compilers are expected to be able to compile to the C99 language standard, 322as some C99 features are used in the source code. Microsoft Visual Studio 323doesn't fully support C99 so in practice shared code is limited to using C99 324features that it does support. 325 326### gcc 327 328The minimum accepted version of gcc is 5.0. Older versions will generate a warning 329by `configure` and are unlikely to work. 330 331The JDK is currently known to be able to compile with at least version 9.2 of 332gcc. 333 334In general, any version between these two should be usable. 335 336### clang 337 338The minimum accepted version of clang is 3.2. Older versions will not be 339accepted by `configure`. 340 341To use clang instead of gcc on Linux, use `--with-toolchain-type=clang`. 342 343### Apple Xcode 344 345The oldest supported version of Xcode is 8. 346 347You will need the Xcode command lines developers tools to be able to build 348the JDK. (Actually, *only* the command lines tools are needed, not the IDE.) 349The simplest way to install these is to run: 350``` 351xcode-select --install 352``` 353 354It is advisable to keep an older version of Xcode for building the JDK when 355updating Xcode. This [blog page]( 356http://iosdevelopertips.com/xcode/install-multiple-versions-of-xcode.html) has 357good suggestions on managing multiple Xcode versions. To use a specific version 358of Xcode, use `xcode-select -s` before running `configure`, or use 359`--with-toolchain-path` to point to the version of Xcode to use, e.g. 360`configure --with-toolchain-path=/Applications/Xcode8.app/Contents/Developer/usr/bin` 361 362If you have recently (inadvertently) updated your OS and/or Xcode version, and 363the JDK can no longer be built, please see the section on [Problems with the 364Build Environment](#problems-with-the-build-environment), and [Getting 365Help](#getting-help) to find out if there are any recent, non-merged patches 366available for this update. 367 368### Microsoft Visual Studio 369 370The minimum accepted version of Visual Studio is 2010. Older versions will not 371be accepted by `configure`. The maximum accepted version of Visual Studio is 3722019. Versions older than 2017 are unlikely to continue working for long. 373 374If you have multiple versions of Visual Studio installed, `configure` will by 375default pick the latest. You can request a specific version to be used by 376setting `--with-toolchain-version`, e.g. `--with-toolchain-version=2015`. 377 378If you get `LINK: fatal error LNK1123: failure during conversion to COFF: file 379invalid` when building using Visual Studio 2010, you have encountered 380[KB2757355](http://support.microsoft.com/kb/2757355), a bug triggered by a 381specific installation order. However, the solution suggested by the KB article 382does not always resolve the problem. See [this stackoverflow discussion]( 383https://stackoverflow.com/questions/10888391) for other suggestions. 384 385### IBM XL C/C++ 386 387Please consult the AIX section of the [Supported Build Platforms]( 388https://wiki.openjdk.java.net/display/Build/Supported+Build+Platforms) OpenJDK 389Build Wiki page for details about which versions of XLC are supported. 390 391 392## Boot JDK Requirements 393 394Paradoxically, building the JDK requires a pre-existing JDK. This is called the 395"boot JDK". The boot JDK does not, however, have to be a JDK built directly from 396the source code available in the OpenJDK Community. If you are porting the JDK 397to a new platform, chances are that there already exists another JDK for that 398platform that is usable as boot JDK. 399 400The rule of thumb is that the boot JDK for building JDK major version *N* 401should be a JDK of major version *N-1*, so for building JDK 9 a JDK 8 would be 402suitable as boot JDK. However, the JDK should be able to "build itself", so an 403up-to-date build of the current JDK source is an acceptable alternative. If 404you are following the *N-1* rule, make sure you've got the latest update 405version, since JDK 8 GA might not be able to build JDK 9 on all platforms. 406 407Early in the release cycle, version *N-1* may not yet have been released. In 408that case, the preferred boot JDK will be version *N-2* until version *N-1* 409is available. 410 411If the boot JDK is not automatically detected, or the wrong JDK is picked, use 412`--with-boot-jdk` to point to the JDK to use. 413 414### Getting JDK binaries 415 416JDK binaries for Linux, Windows and macOS can be downloaded from 417[jdk.java.net](http://jdk.java.net). An alternative is to download the 418[Oracle JDK](http://www.oracle.com/technetwork/java/javase/downloads). Another 419is the [Adopt OpenJDK Project](https://adoptopenjdk.net/), which publishes 420experimental prebuilt binaries for various platforms. 421 422On Linux you can also get a JDK from the Linux distribution. On apt-based 423distros (like Debian and Ubuntu), `sudo apt-get install openjdk-<VERSION>-jdk` 424is typically enough to install a JDK \<VERSION\>. On rpm-based distros (like 425Fedora and Red Hat), try `sudo yum install java-<VERSION>-openjdk-devel`. 426 427## External Library Requirements 428 429Different platforms require different external libraries. In general, libraries 430are not optional - that is, they are either required or not used. 431 432If a required library is not detected by `configure`, you need to provide the 433path to it. There are two forms of the `configure` arguments to point to an 434external library: `--with-<LIB>=<path>` or `--with-<LIB>-include=<path to 435include> --with-<LIB>-lib=<path to lib>`. The first variant is more concise, 436but require the include files and library files to reside in a default 437hierarchy under this directory. In most cases, it works fine. 438 439As a fallback, the second version allows you to point to the include directory 440and the lib directory separately. 441 442### FreeType 443 444FreeType2 from [The FreeType Project](http://www.freetype.org/) is not required 445on any platform. The exception is on Unix-based platforms when configuring such 446that the build artifacts will reference a system installed library, 447rather than bundling the JDK's own copy. 448 449 * To install on an apt-based Linux, try running `sudo apt-get install 450 libfreetype6-dev`. 451 * To install on an rpm-based Linux, try running `sudo yum install 452 freetype-devel`. 453 454Use `--with-freetype-include=<path>` and `--with-freetype-lib=<path>` 455if `configure` does not automatically locate the platform FreeType files. 456 457### CUPS 458 459CUPS, [Common UNIX Printing System](http://www.cups.org) header files are 460required on all platforms, except Windows. Often these files are provided by 461your operating system. 462 463 * To install on an apt-based Linux, try running `sudo apt-get install 464 libcups2-dev`. 465 * To install on an rpm-based Linux, try running `sudo yum install 466 cups-devel`. 467 468Use `--with-cups=<path>` if `configure` does not properly locate your CUPS 469files. 470 471### X11 472 473Certain [X11](http://www.x.org/) libraries and include files are required on 474Linux. 475 476 * To install on an apt-based Linux, try running `sudo apt-get install 477 libx11-dev libxext-dev libxrender-dev libxrandr-dev libxtst-dev libxt-dev`. 478 * To install on an rpm-based Linux, try running `sudo yum install 479 libXtst-devel libXt-devel libXrender-devel libXrandr-devel libXi-devel`. 480 481Use `--with-x=<path>` if `configure` does not properly locate your X11 files. 482 483### ALSA 484 485ALSA, [Advanced Linux Sound Architecture](https://www.alsa-project.org/) is 486required on Linux. At least version 0.9.1 of ALSA is required. 487 488 * To install on an apt-based Linux, try running `sudo apt-get install 489 libasound2-dev`. 490 * To install on an rpm-based Linux, try running `sudo yum install 491 alsa-lib-devel`. 492 493Use `--with-alsa=<path>` if `configure` does not properly locate your ALSA 494files. 495 496### libffi 497 498libffi, the [Portable Foreign Function Interface Library]( 499http://sourceware.org/libffi) is required when building the Zero version of 500Hotspot. 501 502 * To install on an apt-based Linux, try running `sudo apt-get install 503 libffi-dev`. 504 * To install on an rpm-based Linux, try running `sudo yum install 505 libffi-devel`. 506 507Use `--with-libffi=<path>` if `configure` does not properly locate your libffi 508files. 509 510## Build Tools Requirements 511 512### Autoconf 513 514The JDK requires [Autoconf](http://www.gnu.org/software/autoconf) on all 515platforms. At least version 2.69 is required. 516 517 * To install on an apt-based Linux, try running `sudo apt-get install 518 autoconf`. 519 * To install on an rpm-based Linux, try running `sudo yum install 520 autoconf`. 521 * To install on macOS, try running `brew install autoconf`. 522 * To install on Windows, try running `<path to Cygwin setup>/setup-x86_64 -q 523 -P autoconf`. 524 525If `configure` has problems locating your installation of autoconf, you can 526specify it using the `AUTOCONF` environment variable, like this: 527 528``` 529AUTOCONF=<path to autoconf> configure ... 530``` 531 532### GNU Make 533 534The JDK requires [GNU Make](http://www.gnu.org/software/make). No other flavors 535of make are supported. 536 537At least version 3.81 of GNU Make must be used. For distributions supporting 538GNU Make 4.0 or above, we strongly recommend it. GNU Make 4.0 contains useful 539functionality to handle parallel building (supported by `--with-output-sync`) 540and speed and stability improvements. 541 542Note that `configure` locates and verifies a properly functioning version of 543`make` and stores the path to this `make` binary in the configuration. If you 544start a build using `make` on the command line, you will be using the version 545of make found first in your `PATH`, and not necessarily the one stored in the 546configuration. This initial make will be used as "bootstrap make", and in a 547second stage, the make located by `configure` will be called. Normally, this 548will present no issues, but if you have a very old `make`, or a non-GNU Make 549`make` in your path, this might cause issues. 550 551If you want to override the default make found by `configure`, use the `MAKE` 552configure variable, e.g. `configure MAKE=/opt/gnu/make`. 553 554### GNU Bash 555 556The JDK requires [GNU Bash](http://www.gnu.org/software/bash). No other shells 557are supported. 558 559At least version 3.2 of GNU Bash must be used. 560 561## Running Configure 562 563To build the JDK, you need a "configuration", which consists of a directory 564where to store the build output, coupled with information about the platform, 565the specific build machine, and choices that affect how the JDK is built. 566 567The configuration is created by the `configure` script. The basic invocation of 568the `configure` script looks like this: 569 570``` 571bash configure [options] 572``` 573 574This will create an output directory containing the configuration and setup an 575area for the build result. This directory typically looks like 576`build/linux-x64-server-release`, but the actual name depends on your specific 577configuration. (It can also be set directly, see [Using Multiple 578Configurations](#using-multiple-configurations)). This directory is referred to 579as `$BUILD` in this documentation. 580 581`configure` will try to figure out what system you are running on and where all 582necessary build components are. If you have all prerequisites for building 583installed, it should find everything. If it fails to detect any component 584automatically, it will exit and inform you about the problem. 585 586Some command line examples: 587 588 * Create a 32-bit build for Windows with FreeType2 in `C:\freetype-i586`: 589 ``` 590 bash configure --with-freetype=/cygdrive/c/freetype-i586 --with-target-bits=32 591 ``` 592 593 * Create a debug build with the `server` JVM and DTrace enabled: 594 ``` 595 bash configure --enable-debug --with-jvm-variants=server --enable-dtrace 596 ``` 597 598### Common Configure Arguments 599 600Here follows some of the most common and important `configure` argument. 601 602To get up-to-date information on *all* available `configure` argument, please 603run: 604``` 605bash configure --help 606``` 607 608(Note that this help text also include general autoconf options, like 609`--dvidir`, that is not relevant to the JDK. To list only JDK-specific 610features, use `bash configure --help=short` instead.) 611 612#### Configure Arguments for Tailoring the Build 613 614 * `--enable-debug` - Set the debug level to `fastdebug` (this is a shorthand 615 for `--with-debug-level=fastdebug`) 616 * `--with-debug-level=<level>` - Set the debug level, which can be `release`, 617 `fastdebug`, `slowdebug` or `optimized`. Default is `release`. `optimized` 618 is variant of `release` with additional Hotspot debug code. 619 * `--with-native-debug-symbols=<method>` - Specify if and how native debug 620 symbols should be built. Available methods are `none`, `internal`, 621 `external`, `zipped`. Default behavior depends on platform. See [Native 622 Debug Symbols](#native-debug-symbols) for more details. 623 * `--with-version-string=<string>` - Specify the version string this build 624 will be identified with. 625 * `--with-version-<part>=<value>` - A group of options, where `<part>` can be 626 any of `pre`, `opt`, `build`, `major`, `minor`, `security` or `patch`. Use 627 these options to modify just the corresponding part of the version string 628 from the default, or the value provided by `--with-version-string`. 629 * `--with-jvm-variants=<variant>[,<variant>...]` - Build the specified variant 630 (or variants) of Hotspot. Valid variants are: `server`, `client`, 631 `minimal`, `core`, `zero`, `custom`. Note that not all 632 variants are possible to combine in a single build. 633 * `--enable-jvm-feature-<feature>` or `--disable-jvm-feature-<feature>` - 634 Include (or exclude) `<feature>` as a JVM feature in Hotspot. You can also 635 specify a list of features to be enabled, separated by space or comma, as 636 `--with-jvm-features=<feature>[,<feature>...]`. If you prefix `<feature>` 637 with a `-`, it will be disabled. These options will modify the default list 638 of features for the JVM variant(s) you are building. For the `custom` JVM 639 variant, the default list is empty. A complete list of valid JVM features 640 can be found using `bash configure --help`. 641 * `--with-target-bits=<bits>` - Create a target binary suitable for running 642 on a `<bits>` platform. Use this to create 32-bit output on a 64-bit build 643 platform, instead of doing a full cross-compile. (This is known as a 644 *reduced* build.) 645 646On Linux, BSD and AIX, it is possible to override where Java by default 647searches for runtime/JNI libraries. This can be useful in situations where 648there is a special shared directory for system JNI libraries. This setting 649can in turn be overriden at runtime by setting the `java.library.path` property. 650 651 * `--with-jni-libpath=<path>` - Use the specified path as a default 652 when searching for runtime libraries. 653 654#### Configure Arguments for Native Compilation 655 656 * `--with-devkit=<path>` - Use this devkit for compilers, tools and resources 657 * `--with-sysroot=<path>` - Use this directory as sysroot 658 * `--with-extra-path=<path>[;<path>]` - Prepend these directories to the 659 default path when searching for all kinds of binaries 660 * `--with-toolchain-path=<path>[;<path>]` - Prepend these directories when 661 searching for toolchain binaries (compilers etc) 662 * `--with-extra-cflags=<flags>` - Append these flags when compiling JDK C 663 files 664 * `--with-extra-cxxflags=<flags>` - Append these flags when compiling JDK C++ 665 files 666 * `--with-extra-ldflags=<flags>` - Append these flags when linking JDK 667 libraries 668 669#### Configure Arguments for External Dependencies 670 671 * `--with-boot-jdk=<path>` - Set the path to the [Boot JDK]( 672 #boot-jdk-requirements) 673 * `--with-freetype=<path>` - Set the path to [FreeType](#freetype) 674 * `--with-cups=<path>` - Set the path to [CUPS](#cups) 675 * `--with-x=<path>` - Set the path to [X11](#x11) 676 * `--with-alsa=<path>` - Set the path to [ALSA](#alsa) 677 * `--with-libffi=<path>` - Set the path to [libffi](#libffi) 678 * `--with-jtreg=<path>` - Set the path to JTReg. See [Running Tests]( 679 #running-tests) 680 681Certain third-party libraries used by the JDK (libjpeg, giflib, libpng, lcms 682and zlib) are included in the JDK repository. The default behavior of the 683JDK build is to use the included ("bundled") versions of libjpeg, giflib, 684libpng and lcms. 685For zlib, the system lib (if present) is used except on Windows and AIX. 686However the bundled libraries may be replaced by an external version. 687To do so, specify `system` as the `<source>` option in these arguments. 688(The default is `bundled`). 689 690 * `--with-libjpeg=<source>` - Use the specified source for libjpeg 691 * `--with-giflib=<source>` - Use the specified source for giflib 692 * `--with-libpng=<source>` - Use the specified source for libpng 693 * `--with-lcms=<source>` - Use the specified source for lcms 694 * `--with-zlib=<source>` - Use the specified source for zlib 695 696On Linux, it is possible to select either static or dynamic linking of the C++ 697runtime. The default is static linking, with dynamic linking as fallback if the 698static library is not found. 699 700 * `--with-stdc++lib=<method>` - Use the specified method (`static`, `dynamic` 701 or `default`) for linking the C++ runtime. 702 703### Configure Control Variables 704 705It is possible to control certain aspects of `configure` by overriding the 706value of `configure` variables, either on the command line or in the 707environment. 708 709Normally, this is **not recommended**. If used improperly, it can lead to a 710broken configuration. Unless you're well versed in the build system, this is 711hard to use properly. Therefore, `configure` will print a warning if this is 712detected. 713 714However, there are a few `configure` variables, known as *control variables* 715that are supposed to be overriden on the command line. These are variables that 716describe the location of tools needed by the build, like `MAKE` or `GREP`. If 717any such variable is specified, `configure` will use that value instead of 718trying to autodetect the tool. For instance, `bash configure 719MAKE=/opt/gnumake4.0/bin/make`. 720 721If a configure argument exists, use that instead, e.g. use `--with-jtreg` 722instead of setting `JTREGEXE`. 723 724Also note that, despite what autoconf claims, setting `CFLAGS` will not 725accomplish anything. Instead use `--with-extra-cflags` (and similar for 726`cxxflags` and `ldflags`). 727 728## Running Make 729 730When you have a proper configuration, all you need to do to build the JDK is to 731run `make`. (But see the warning at [GNU Make](#gnu-make) about running the 732correct version of make.) 733 734When running `make` without any arguments, the default target is used, which is 735the same as running `make default` or `make jdk`. This will build a minimal (or 736roughly minimal) set of compiled output (known as an "exploded image") needed 737for a developer to actually execute the newly built JDK. The idea is that in an 738incremental development fashion, when doing a normal make, you should only 739spend time recompiling what's changed (making it purely incremental) and only 740do the work that's needed to actually run and test your code. 741 742The output of the exploded image resides in `$BUILD/jdk`. You can test the 743newly built JDK like this: `$BUILD/jdk/bin/java -version`. 744 745### Common Make Targets 746 747Apart from the default target, here are some common make targets: 748 749 * `hotspot` - Build all of hotspot (but only hotspot) 750 * `hotspot-<variant>` - Build just the specified jvm variant 751 * `images` or `product-images` - Build the JDK image 752 * `docs` or `docs-image` - Build the documentation image 753 * `test-image` - Build the test image 754 * `all` or `all-images` - Build all images (product, docs and test) 755 * `bootcycle-images` - Build images twice, second time with newly built JDK 756 (good for testing) 757 * `clean` - Remove all files generated by make, but not those generated by 758 configure 759 * `dist-clean` - Remove all files, including configuration 760 761Run `make help` to get an up-to-date list of important make targets and make 762control variables. 763 764It is possible to build just a single module, a single phase, or a single phase 765of a single module, by creating make targets according to these followin 766patterns. A phase can be either of `gensrc`, `gendata`, `copy`, `java`, 767`launchers`, or `libs`. See [Using Fine-Grained Make Targets]( 768#using-fine-grained-make-targets) for more details about this functionality. 769 770 * `<phase>` - Build the specified phase and everything it depends on 771 * `<module>` - Build the specified module and everything it depends on 772 * `<module>-<phase>` - Compile the specified phase for the specified module 773 and everything it depends on 774 775Similarly, it is possible to clean just a part of the build by creating make 776targets according to these patterns: 777 778 * `clean-<outputdir>` - Remove the subdir in the output dir with the name 779 * `clean-<phase>` - Remove all build results related to a certain build 780 phase 781 * `clean-<module>` - Remove all build results related to a certain module 782 * `clean-<module>-<phase>` - Remove all build results related to a certain 783 module and phase 784 785### Make Control Variables 786 787It is possible to control `make` behavior by overriding the value of `make` 788variables, either on the command line or in the environment. 789 790Normally, this is **not recommended**. If used improperly, it can lead to a 791broken build. Unless you're well versed in the build system, this is hard to 792use properly. Therefore, `make` will print a warning if this is detected. 793 794However, there are a few `make` variables, known as *control variables* that 795are supposed to be overriden on the command line. These make up the "make time" 796configuration, as opposed to the "configure time" configuration. 797 798#### General Make Control Variables 799 800 * `JOBS` - Specify the number of jobs to build with. See [Build 801 Performance](#build-performance). 802 * `LOG` - Specify the logging level and functionality. See [Checking the 803 Build Log File](#checking-the-build-log-file) 804 * `CONF` and `CONF_NAME` - Selecting the configuration(s) to use. See [Using 805 Multiple Configurations](#using-multiple-configurations) 806 807#### Test Make Control Variables 808 809These make control variables only make sense when running tests. Please see 810[Testing the JDK](testing.html) for details. 811 812 * `TEST` 813 * `TEST_JOBS` 814 * `JTREG` 815 * `GTEST` 816 817#### Advanced Make Control Variables 818 819These advanced make control variables can be potentially unsafe. See [Hints and 820Suggestions for Advanced Users](#hints-and-suggestions-for-advanced-users) and 821[Understanding the Build System](#understanding-the-build-system) for details. 822 823 * `SPEC` 824 * `CONF_CHECK` 825 * `COMPARE_BUILD` 826 * `JDK_FILTER` 827 * `SPEC_FILTER` 828 829## Running Tests 830 831Most of the JDK tests are using the [JTReg](http://openjdk.java.net/jtreg) 832test framework. Make sure that your configuration knows where to find your 833installation of JTReg. If this is not picked up automatically, use the 834`--with-jtreg=<path to jtreg home>` option to point to the JTReg framework. 835Note that this option should point to the JTReg home, i.e. the top directory, 836containing `lib/jtreg.jar` etc. 837 838The [Adoption Group](https://wiki.openjdk.java.net/display/Adoption) provides 839recent builds of jtreg [here]( 840https://ci.adoptopenjdk.net/view/Dependencies/job/jtreg/lastSuccessfulBuild/artifact). 841Download the latest `.tar.gz` file, unpack it, and point `--with-jtreg` to the 842`jtreg` directory that you just unpacked. 843 844Building of Hotspot Gtest suite requires the source code of Google Test framework. 845The top directory, which contains both `googletest` and `googlemock` 846directories, should be specified via `--with-gtest`. 847The supported version of Google Test is 1.8.1, whose source code can be obtained: 848 849 * by downloading and unpacking the source bundle from [here](https://github.com/google/googletest/releases/tag/release-1.8.1) 850 * or by checking out `release-1.8.1` tag of `googletest` project: `git clone -b release-1.8.1 https://github.com/google/googletest` 851 852To execute the most basic tests (tier 1), use: 853``` 854make run-test-tier1 855``` 856 857For more details on how to run tests, please see the [Testing 858the JDK](testing.html) document. 859 860## Cross-compiling 861 862Cross-compiling means using one platform (the *build* platform) to generate 863output that can ran on another platform (the *target* platform). 864 865The typical reason for cross-compiling is that the build is performed on a more 866powerful desktop computer, but the resulting binaries will be able to run on a 867different, typically low-performing system. Most of the complications that 868arise when building for embedded is due to this separation of *build* and 869*target* systems. 870 871This requires a more complex setup and build procedure. This section assumes 872you are familiar with cross-compiling in general, and will only deal with the 873particularities of cross-compiling the JDK. If you are new to cross-compiling, 874please see the [external links at Wikipedia]( 875https://en.wikipedia.org/wiki/Cross_compiler#External_links) for a good start 876on reading materials. 877 878Cross-compiling the JDK requires you to be able to build both for the build 879platform and for the target platform. The reason for the former is that we need 880to build and execute tools during the build process, both native tools and Java 881tools. 882 883If all you want to do is to compile a 32-bit version, for the same OS, on a 88464-bit machine, consider using `--with-target-bits=32` instead of doing a 885full-blown cross-compilation. (While this surely is possible, it's a lot more 886work and will take much longer to build.) 887 888### Cross compiling the easy way with OpenJDK devkits 889 890The OpenJDK build system provides out-of-the box support for creating and using 891so called devkits. A `devkit` is basically a collection of a cross-compiling 892toolchain and a sysroot environment which can easily be used together with the 893`--with-devkit` configure option to cross compile the OpenJDK. On Linux/x86_64, 894the following command: 895``` 896bash configure --with-devkit=<devkit-path> --openjdk-target=ppc64-linux-gnu && make 897``` 898 899will configure and build OpenJDK for Linux/ppc64 assuming that `<devkit-path>` 900points to a Linux/x86_64 to Linux/ppc64 devkit. 901 902Devkits can be created from the `make/devkit` directory by executing: 903``` 904make [ TARGETS="<TARGET_TRIPLET>+" ] [ BASE_OS=<OS> ] [ BASE_OS_VERSION=<VER> ] 905``` 906 907where `TARGETS` contains one or more `TARGET_TRIPLET`s of the form 908described in [section 3.4 of the GNU Autobook]( 909https://sourceware.org/autobook/autobook/autobook_17.html). If no 910targets are given, a native toolchain for the current platform will be 911created. Currently, at least the following targets are known to work: 912 913 Supported devkit targets 914 ------------------------- 915 x86_64-linux-gnu 916 aarch64-linux-gnu 917 arm-linux-gnueabihf 918 ppc64-linux-gnu 919 ppc64le-linux-gnu 920 s390x-linux-gnu 921 922`BASE_OS` must be one of "OEL6" for Oracle Enterprise Linux 6 or 923"Fedora" (if not specified "OEL6" will be the default). If the base OS 924is "Fedora" the corresponding Fedora release can be specified with the 925help of the `BASE_OS_VERSION` option (with "27" as default version). 926If the build is successful, the new devkits can be found in the 927`build/devkit/result` subdirectory: 928``` 929cd make/devkit 930make TARGETS="ppc64le-linux-gnu aarch64-linux-gnu" BASE_OS=Fedora BASE_OS_VERSION=21 931ls -1 ../../build/devkit/result/ 932x86_64-linux-gnu-to-aarch64-linux-gnu 933x86_64-linux-gnu-to-ppc64le-linux-gnu 934``` 935 936Notice that devkits are not only useful for targeting different build 937platforms. Because they contain the full build dependencies for a 938system (i.e. compiler and root file system), they can easily be used 939to build well-known, reliable and reproducible build environments. You 940can for example create and use a devkit with GCC 7.3 and a Fedora 12 941sysroot environment (with glibc 2.11) on Ubuntu 14.04 (which doesn't 942have GCC 7.3 by default) to produce OpenJDK binaries which will run on 943all Linux systems with runtime libraries newer than the ones from 944Fedora 12 (e.g. Ubuntu 16.04, SLES 11 or RHEL 6). 945 946### Boot JDK and Build JDK 947 948When cross-compiling, make sure you use a boot JDK that runs on the *build* 949system, and not on the *target* system. 950 951To be able to build, we need a "Build JDK", which is a JDK built from the 952current sources (that is, the same as the end result of the entire build 953process), but able to run on the *build* system, and not the *target* system. 954(In contrast, the Boot JDK should be from an older release, e.g. JDK 8 when 955building JDK 9.) 956 957The build process will create a minimal Build JDK for you, as part of building. 958To speed up the build, you can use `--with-build-jdk` to `configure` to point 959to a pre-built Build JDK. Please note that the build result is unpredictable, 960and can possibly break in subtle ways, if the Build JDK does not **exactly** 961match the current sources. 962 963### Specifying the Target Platform 964 965You *must* specify the target platform when cross-compiling. Doing so will also 966automatically turn the build into a cross-compiling mode. The simplest way to 967do this is to use the `--openjdk-target` argument, e.g. 968`--openjdk-target=arm-linux-gnueabihf`. or `--openjdk-target=aarch64-oe-linux`. 969This will automatically set the `--build`, `--host` and `--target` options for 970autoconf, which can otherwise be confusing. (In autoconf terminology, the 971"target" is known as "host", and "target" is used for building a Canadian 972cross-compiler.) 973 974### Toolchain Considerations 975 976You will need two copies of your toolchain, one which generates output that can 977run on the target system (the normal, or *target*, toolchain), and one that 978generates output that can run on the build system (the *build* toolchain). Note 979that cross-compiling is only supported for gcc at the time being. The gcc 980standard is to prefix cross-compiling toolchains with the target denominator. 981If you follow this standard, `configure` is likely to pick up the toolchain 982correctly. 983 984The *build* toolchain will be autodetected just the same way the normal 985*build*/*target* toolchain will be autodetected when not cross-compiling. If 986this is not what you want, or if the autodetection fails, you can specify a 987devkit containing the *build* toolchain using `--with-build-devkit` to 988`configure`, or by giving `BUILD_CC` and `BUILD_CXX` arguments. 989 990It is often helpful to locate the cross-compilation tools, headers and 991libraries in a separate directory, outside the normal path, and point out that 992directory to `configure`. Do this by setting the sysroot (`--with-sysroot`) and 993appending the directory when searching for cross-compilations tools 994(`--with-toolchain-path`). As a compact form, you can also use `--with-devkit` 995to point to a single directory, if it is correctly setup. (See `basics.m4` for 996details.) 997 998### Native Libraries 999 1000You will need copies of external native libraries for the *target* system, 1001present on the *build* machine while building. 1002 1003Take care not to replace the *build* system's version of these libraries by 1004mistake, since that can render the *build* machine unusable. 1005 1006Make sure that the libraries you point to (ALSA, X11, etc) are for the 1007*target*, not the *build*, platform. 1008 1009#### ALSA 1010 1011You will need alsa libraries suitable for your *target* system. For most cases, 1012using Debian's pre-built libraries work fine. 1013 1014Note that alsa is needed even if you only want to build a headless JDK. 1015 1016 * Go to [Debian Package Search](https://www.debian.org/distrib/packages) and 1017 search for the `libasound2` and `libasound2-dev` packages for your *target* 1018 system. Download them to /tmp. 1019 1020 * Install the libraries into the cross-compilation toolchain. For instance: 1021``` 1022cd /tools/gcc-linaro-arm-linux-gnueabihf-raspbian-2012.09-20120921_linux/arm-linux-gnueabihf/libc 1023dpkg-deb -x /tmp/libasound2_1.0.25-4_armhf.deb . 1024dpkg-deb -x /tmp/libasound2-dev_1.0.25-4_armhf.deb . 1025``` 1026 1027 * If alsa is not properly detected by `configure`, you can point it out by 1028 `--with-alsa`. 1029 1030#### X11 1031 1032You will need X11 libraries suitable for your *target* system. For most cases, 1033using Debian's pre-built libraries work fine. 1034 1035Note that X11 is needed even if you only want to build a headless JDK. 1036 1037 * Go to [Debian Package Search](https://www.debian.org/distrib/packages), 1038 search for the following packages for your *target* system, and download them 1039 to /tmp/target-x11: 1040 * libxi 1041 * libxi-dev 1042 * x11proto-core-dev 1043 * x11proto-input-dev 1044 * x11proto-kb-dev 1045 * x11proto-render-dev 1046 * x11proto-xext-dev 1047 * libice-dev 1048 * libxrender 1049 * libxrender-dev 1050 * libxrandr-dev 1051 * libsm-dev 1052 * libxt-dev 1053 * libx11 1054 * libx11-dev 1055 * libxtst 1056 * libxtst-dev 1057 * libxext 1058 * libxext-dev 1059 1060 * Install the libraries into the cross-compilation toolchain. For instance: 1061 ``` 1062 cd /tools/gcc-linaro-arm-linux-gnueabihf-raspbian-2012.09-20120921_linux/arm-linux-gnueabihf/libc/usr 1063 mkdir X11R6 1064 cd X11R6 1065 for deb in /tmp/target-x11/*.deb ; do dpkg-deb -x $deb . ; done 1066 mv usr/* . 1067 cd lib 1068 cp arm-linux-gnueabihf/* . 1069 ``` 1070 1071 You can ignore the following messages. These libraries are not needed to 1072 successfully complete a full JDK build. 1073 ``` 1074 cp: cannot stat `arm-linux-gnueabihf/libICE.so': No such file or directory 1075 cp: cannot stat `arm-linux-gnueabihf/libSM.so': No such file or directory 1076 cp: cannot stat `arm-linux-gnueabihf/libXt.so': No such file or directory 1077 ``` 1078 1079 * If the X11 libraries are not properly detected by `configure`, you can 1080 point them out by `--with-x`. 1081 1082### Creating And Using Sysroots With qemu-deboostrap 1083 1084Fortunately, you can create sysroots for foreign architectures with tools 1085provided by your OS. On Debian/Ubuntu systems, one could use `qemu-deboostrap` to 1086create the *target* system chroot, which would have the native libraries and headers 1087specific to that *target* system. After that, we can use the cross-compiler on the *build* 1088system, pointing into chroot to get the build dependencies right. This allows building 1089for foreign architectures with native compilation speed. 1090 1091For example, cross-compiling to AArch64 from x86_64 could be done like this: 1092 1093 * Install cross-compiler on the *build* system: 1094``` 1095apt install g++-aarch64-linux-gnu gcc-aarch64-linux-gnu 1096``` 1097 1098 * Create chroot on the *build* system, configuring it for *target* system: 1099``` 1100sudo qemu-debootstrap --arch=arm64 --verbose \ 1101 --include=fakeroot,build-essential,libx11-dev,libxext-dev,libxrender-dev,libxrandr-dev,libxtst-dev,libxt-dev,libcups2-dev,libfontconfig1-dev,libasound2-dev,libfreetype6-dev,libpng12-dev \ 1102 --resolve-deps jessie /chroots/arm64 http://httpredir.debian.org/debian/ 1103``` 1104 1105 * Configure and build with newly created chroot as sysroot/toolchain-path: 1106``` 1107CC=aarch64-linux-gnu-gcc CXX=aarch64-linux-gnu-g++ sh ./configure --openjdk-target=aarch64-linux-gnu --with-sysroot=/chroots/arm64/ --with-toolchain-path=/chroots/arm64/ 1108make images 1109ls build/linux-aarch64-normal-server-release/ 1110``` 1111 1112The build does not create new files in that chroot, so it can be reused for multiple builds 1113without additional cleanup. 1114 1115Architectures that are known to successfully cross-compile like this are: 1116 1117 Target `CC` `CXX` `--arch=...` `--openjdk-target=...` 1118 ------------ ------------------------- --------------------------- ------------- ----------------------- 1119 x86 default default i386 i386-linux-gnu 1120 armhf gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf armhf arm-linux-gnueabihf 1121 aarch64 gcc-aarch64-linux-gnu g++-aarch64-linux-gnu arm64 aarch64-linux-gnu 1122 ppc64el gcc-powerpc64le-linux-gnu g++-powerpc64le-linux-gnu ppc64el powerpc64le-linux-gnu 1123 s390x gcc-s390x-linux-gnu g++-s390x-linux-gnu s390x s390x-linux-gnu 1124 1125Additional architectures might be supported by Debian/Ubuntu Ports. 1126 1127### Building for ARM/aarch64 1128 1129A common cross-compilation target is the ARM CPU. When building for ARM, it is 1130useful to set the ABI profile. A number of pre-defined ABI profiles are 1131available using `--with-abi-profile`: arm-vfp-sflt, arm-vfp-hflt, arm-sflt, 1132armv5-vfp-sflt, armv6-vfp-hflt. Note that soft-float ABIs are no longer 1133properly supported by the JDK. 1134 1135### Verifying the Build 1136 1137The build will end up in a directory named like 1138`build/linux-arm-normal-server-release`. 1139 1140Inside this build output directory, the `images/jdk` will contain the newly 1141built JDK, for your *target* system. 1142 1143Copy these folders to your *target* system. Then you can run e.g. 1144`images/jdk/bin/java -version`. 1145 1146## Build Performance 1147 1148Building the JDK requires a lot of horsepower. Some of the build tools can be 1149adjusted to utilize more or less of resources such as parallel threads and 1150memory. The `configure` script analyzes your system and selects reasonable 1151values for such options based on your hardware. If you encounter resource 1152problems, such as out of memory conditions, you can modify the detected values 1153with: 1154 1155 * `--with-num-cores` -- number of cores in the build system, e.g. 1156 `--with-num-cores=8`. 1157 1158 * `--with-memory-size` -- memory (in MB) available in the build system, e.g. 1159 `--with-memory-size=1024` 1160 1161You can also specify directly the number of build jobs to use with 1162`--with-jobs=N` to `configure`, or `JOBS=N` to `make`. Do not use the `-j` flag 1163to `make`. In most cases it will be ignored by the makefiles, but it can cause 1164problems for some make targets. 1165 1166It might also be necessary to specify the JVM arguments passed to the Boot JDK, 1167using e.g. `--with-boot-jdk-jvmargs="-Xmx8G"`. Doing so will override the 1168default JVM arguments passed to the Boot JDK. 1169 1170At the end of a successful execution of `configure`, you will get a performance 1171summary, indicating how well the build will perform. Here you will also get 1172performance hints. If you want to build fast, pay attention to those! 1173 1174If you want to tweak build performance, run with `make LOG=info` to get a build 1175time summary at the end of the build process. 1176 1177### Disk Speed 1178 1179If you are using network shares, e.g. via NFS, for your source code, make sure 1180the build directory is situated on local disk (e.g. by `ln -s 1181/localdisk/jdk-build $JDK-SHARE/build`). The performance penalty is extremely 1182high for building on a network share; close to unusable. 1183 1184Also, make sure that your build tools (including Boot JDK and toolchain) is 1185located on a local disk and not a network share. 1186 1187As has been stressed elsewhere, do use SSD for source code and build directory, 1188as well as (if possible) the build tools. 1189 1190### Virus Checking 1191 1192The use of virus checking software, especially on Windows, can *significantly* 1193slow down building of the JDK. If possible, turn off such software, or exclude 1194the directory containing the JDK source code from on-the-fly checking. 1195 1196### Ccache 1197 1198The JDK build supports building with ccache when using gcc or clang. Using 1199ccache can radically speed up compilation of native code if you often rebuild 1200the same sources. Your milage may vary however, so we recommend evaluating it 1201for yourself. To enable it, make sure it's on the path and configure with 1202`--enable-ccache`. 1203 1204### Precompiled Headers 1205 1206By default, the Hotspot build uses preccompiled headers (PCH) on the toolchains 1207were it is properly supported (clang, gcc, and Visual Studio). Normally, this 1208speeds up the build process, but in some circumstances, it can actually slow 1209things down. 1210 1211You can experiment by disabling precompiled headers using 1212`--disable-precompiled-headers`. 1213 1214### Icecc / icecream 1215 1216[icecc/icecream](http://github.com/icecc/icecream) is a simple way to setup a 1217distributed compiler network. If you have multiple machines available for 1218building the JDK, you can drastically cut individual build times by utilizing 1219it. 1220 1221To use, setup an icecc network, and install icecc on the build machine. Then 1222run `configure` using `--enable-icecc`. 1223 1224### Using sjavac 1225 1226To speed up Java compilation, especially incremental compilations, you can try 1227the experimental sjavac compiler by using `--enable-sjavac`. 1228 1229### Building the Right Target 1230 1231Selecting the proper target to build can have dramatic impact on build time. 1232For normal usage, `jdk` or the default target is just fine. You only need to 1233build `images` for shipping, or if your tests require it. 1234 1235See also [Using Fine-Grained Make Targets](#using-fine-grained-make-targets) on 1236how to build an even smaller subset of the product. 1237 1238## Troubleshooting 1239 1240If your build fails, it can sometimes be difficult to pinpoint the problem or 1241find a proper solution. 1242 1243### Locating the Source of the Error 1244 1245When a build fails, it can be hard to pinpoint the actual cause of the error. 1246In a typical build process, different parts of the product build in parallel, 1247with the output interlaced. 1248 1249#### Build Failure Summary 1250 1251To help you, the build system will print a failure summary at the end. It looks 1252like this: 1253 1254``` 1255ERROR: Build failed for target 'hotspot' in configuration 'linux-x64' (exit code 2) 1256 1257=== Output from failing command(s) repeated here === 1258* For target hotspot_variant-server_libjvm_objs_psMemoryPool.o: 1259/localhome/git/jdk-sandbox/hotspot/src/share/vm/services/psMemoryPool.cpp:1:1: error: 'failhere' does not name a type 1260 ... (rest of output omitted) 1261 1262* All command lines available in /localhome/git/jdk-sandbox/build/linux-x64/make-support/failure-logs. 1263=== End of repeated output === 1264 1265=== Make failed targets repeated here === 1266lib/CompileJvm.gmk:207: recipe for target '/localhome/git/jdk-sandbox/build/linux-x64/hotspot/variant-server/libjvm/objs/psMemoryPool.o' failed 1267make/Main.gmk:263: recipe for target 'hotspot-server-libs' failed 1268=== End of repeated output === 1269 1270Hint: Try searching the build log for the name of the first failed target. 1271Hint: If caused by a warning, try configure --disable-warnings-as-errors. 1272``` 1273 1274Let's break it down! First, the selected configuration, and the top-level 1275target you entered on the command line that caused the failure is printed. 1276 1277Then, between the `Output from failing command(s) repeated here` and `End of 1278repeated output` the first lines of output (stdout and stderr) from the actual 1279failing command is repeated. In most cases, this is the error message that 1280caused the build to fail. If multiple commands were failing (this can happen in 1281a parallel build), output from all failed commands will be printed here. 1282 1283The path to the `failure-logs` directory is printed. In this file you will find 1284a `<target>.log` file that contains the output from this command in its 1285entirety, and also a `<target>.cmd`, which contain the complete command line 1286used for running this command. You can re-run the failing command by executing 1287`. <path to failure-logs>/<target>.cmd` in your shell. 1288 1289Another way to trace the failure is to follow the chain of make targets, from 1290top-level targets to individual file targets. Between `Make failed targets 1291repeated here` and `End of repeated output` the output from make showing this 1292chain is repeated. The first failed recipe will typically contain the full path 1293to the file in question that failed to compile. Following lines will show a 1294trace of make targets why we ended up trying to compile that file. 1295 1296Finally, some hints are given on how to locate the error in the complete log. 1297In this example, we would try searching the log file for "`psMemoryPool.o`". 1298Another way to quickly locate make errors in the log is to search for "`] 1299Error`" or "`***`". 1300 1301Note that the build failure summary will only help you if the issue was a 1302compilation failure or similar. If the problem is more esoteric, or is due to 1303errors in the build machinery, you will likely get empty output logs, and `No 1304indication of failed target found` instead of the make target chain. 1305 1306#### Checking the Build Log File 1307 1308The output (stdout and stderr) from the latest build is always stored in 1309`$BUILD/build.log`. The previous build log is stored as `build.log.old`. This 1310means that it is not necessary to redirect the build output yourself if you 1311want to process it. 1312 1313You can increase the verbosity of the log file, by the `LOG` control variable 1314to `make`. If you want to see the command lines used in compilations, use 1315`LOG=cmdlines`. To increase the general verbosity, use `LOG=info`, `LOG=debug` 1316or `LOG=trace`. Both of these can be combined with `cmdlines`, e.g. 1317`LOG=info,cmdlines`. The `debug` log level will show most shell commands 1318executed by make, and `trace` will show all. Beware that both these log levels 1319will produce a massive build log! 1320 1321### Fixing Unexpected Build Failures 1322 1323Most of the time, the build will fail due to incorrect changes in the source 1324code. 1325 1326Sometimes the build can fail with no apparent changes that have caused the 1327failure. If this is the first time you are building the JDK on this particular 1328computer, and the build fails, the problem is likely with your build 1329environment. But even if you have previously built the JDK with success, and it 1330now fails, your build environment might have changed (perhaps due to OS 1331upgrades or similar). But most likely, such failures are due to problems with 1332the incremental rebuild. 1333 1334#### Problems with the Build Environment 1335 1336Make sure your configuration is correct. Re-run `configure`, and look for any 1337warnings. Warnings that appear in the middle of the `configure` output is also 1338repeated at the end, after the summary. The entire log is stored in 1339`$BUILD/configure.log`. 1340 1341Verify that the summary at the end looks correct. Are you indeed using the Boot 1342JDK and native toolchain that you expect? 1343 1344By default, the JDK has a strict approach where warnings from the compiler is 1345considered errors which fail the build. For very new or very old compiler 1346versions, this can trigger new classes of warnings, which thus fails the build. 1347Run `configure` with `--disable-warnings-as-errors` to turn of this behavior. 1348(The warnings will still show, but not make the build fail.) 1349 1350#### Problems with Incremental Rebuilds 1351 1352Incremental rebuilds mean that when you modify part of the product, only the 1353affected parts get rebuilt. While this works great in most cases, and 1354significantly speed up the development process, from time to time complex 1355interdependencies will result in an incorrect build result. This is the most 1356common cause for unexpected build problems. 1357 1358Here are a suggested list of things to try if you are having unexpected build 1359problems. Each step requires more time than the one before, so try them in 1360order. Most issues will be solved at step 1 or 2. 1361 1362 1. Make sure your repository is up-to-date 1363 1364 Run `git pull origin master` to make sure you have the latest changes. 1365 1366 2. Clean build results 1367 1368 The simplest way to fix incremental rebuild issues is to run `make clean`. 1369 This will remove all build results, but not the configuration or any build 1370 system support artifacts. In most cases, this will solve build errors 1371 resulting from incremental build mismatches. 1372 1373 3. Completely clean the build directory. 1374 1375 If this does not work, the next step is to run `make dist-clean`, or 1376 removing the build output directory (`$BUILD`). This will clean all 1377 generated output, including your configuration. You will need to re-run 1378 `configure` after this step. A good idea is to run `make 1379 print-configuration` before running `make dist-clean`, as this will print 1380 your current `configure` command line. Here's a way to do this: 1381 1382 ``` 1383 make print-configuration > current-configuration 1384 make dist-clean 1385 bash configure $(cat current-configuration) 1386 make 1387 ``` 1388 1389 4. Re-clone the Git repository 1390 1391 Sometimes the Git repository gets in a state that causes the product 1392 to be un-buildable. In such a case, the simplest solution is often the 1393 "sledgehammer approach": delete the entire repository, and re-clone it. 1394 If you have local changes, save them first to a different location using 1395 `git format-patch`. 1396 1397### Specific Build Issues 1398 1399#### Clock Skew 1400 1401If you get an error message like this: 1402``` 1403File 'xxx' has modification time in the future. 1404Clock skew detected. Your build may be incomplete. 1405``` 1406then the clock on your build machine is out of sync with the timestamps on the 1407source files. Other errors, apparently unrelated but in fact caused by the 1408clock skew, can occur along with the clock skew warnings. These secondary 1409errors may tend to obscure the fact that the true root cause of the problem is 1410an out-of-sync clock. 1411 1412If you see these warnings, reset the clock on the build machine, run `make 1413clean` and restart the build. 1414 1415#### Out of Memory Errors 1416 1417On Windows, you might get error messages like this: 1418``` 1419fatal error - couldn't allocate heap 1420cannot create ... Permission denied 1421spawn failed 1422``` 1423This can be a sign of a Cygwin problem. See the information about solving 1424problems in the [Cygwin](#cygwin) section. Rebooting the computer might help 1425temporarily. 1426 1427### Getting Help 1428 1429If none of the suggestions in this document helps you, or if you find what you 1430believe is a bug in the build system, please contact the Build Group by sending 1431a mail to [build-dev@openjdk.java.net](mailto:build-dev@openjdk.java.net). 1432Please include the relevant parts of the configure and/or build log. 1433 1434If you need general help or advice about developing for the JDK, you can also 1435contact the Adoption Group. See the section on [Contributing to OpenJDK]( 1436#contributing-to-openjdk) for more information. 1437 1438## Hints and Suggestions for Advanced Users 1439 1440### Bash Completion 1441 1442The `configure` and `make` commands tries to play nice with bash command-line 1443completion (using `<tab>` or `<tab><tab>`). To use this functionality, make 1444sure you enable completion in your `~/.bashrc` (see instructions for bash in 1445your operating system). 1446 1447Make completion will work out of the box, and will complete valid make targets. 1448For instance, typing `make jdk-i<tab>` will complete to `make jdk-image`. 1449 1450The `configure` script can get completion for options, but for this to work you 1451need to help `bash` on the way. The standard way of running the script, `bash 1452configure`, will not be understood by bash completion. You need `configure` to 1453be the command to run. One way to achieve this is to add a simple helper script 1454to your path: 1455 1456``` 1457cat << EOT > /tmp/configure 1458#!/bin/bash 1459if [ \$(pwd) = \$(cd \$(dirname \$0); pwd) ] ; then 1460 echo >&2 "Abort: Trying to call configure helper recursively" 1461 exit 1 1462fi 1463 1464bash \$PWD/configure "\$@" 1465EOT 1466chmod +x /tmp/configure 1467sudo mv /tmp/configure /usr/local/bin 1468``` 1469 1470Now `configure --en<tab>-dt<tab>` will result in `configure --enable-dtrace`. 1471 1472### Using Multiple Configurations 1473 1474You can have multiple configurations for a single source repository. When you 1475create a new configuration, run `configure --with-conf-name=<name>` to create a 1476configuration with the name `<name>`. Alternatively, you can create a directory 1477under `build` and run `configure` from there, e.g. `mkdir build/<name> && cd 1478build/<name> && bash ../../configure`. 1479 1480Then you can build that configuration using `make CONF_NAME=<name>` or `make 1481CONF=<pattern>`, where `<pattern>` is a substring matching one or several 1482configurations, e.g. `CONF=debug`. The special empty pattern (`CONF=`) will 1483match *all* available configuration, so `make CONF= hotspot` will build the 1484`hotspot` target for all configurations. Alternatively, you can execute `make` 1485in the configuration directory, e.g. `cd build/<name> && make`. 1486 1487### Handling Reconfigurations 1488 1489If you update the repository and part of the configure script has changed, the 1490build system will force you to re-run `configure`. 1491 1492Most of the time, you will be fine by running `configure` again with the same 1493arguments as the last time, which can easily be performed by `make 1494reconfigure`. To simplify this, you can use the `CONF_CHECK` make control 1495variable, either as `make CONF_CHECK=auto`, or by setting an environment 1496variable. For instance, if you add `export CONF_CHECK=auto` to your `.bashrc` 1497file, `make` will always run `reconfigure` automatically whenever the configure 1498script has changed. 1499 1500You can also use `CONF_CHECK=ignore` to skip the check for a needed configure 1501update. This might speed up the build, but comes at the risk of an incorrect 1502build result. This is only recommended if you know what you're doing. 1503 1504From time to time, you will also need to modify the command line to `configure` 1505due to changes. Use `make print-configure` to show the command line used for 1506your current configuration. 1507 1508### Using Fine-Grained Make Targets 1509 1510The default behavior for make is to create consistent and correct output, at 1511the expense of build speed, if necessary. 1512 1513If you are prepared to take some risk of an incorrect build, and know enough of 1514the system to understand how things build and interact, you can speed up the 1515build process considerably by instructing make to only build a portion of the 1516product. 1517 1518#### Building Individual Modules 1519 1520The safe way to use fine-grained make targets is to use the module specific 1521make targets. All source code in the JDK is organized so it belongs to a 1522module, e.g. `java.base` or `jdk.jdwp.agent`. You can build only a specific 1523module, by giving it as make target: `make jdk.jdwp.agent`. If the specified 1524module depends on other modules (e.g. `java.base`), those modules will be built 1525first. 1526 1527You can also specify a set of modules, just as you can always specify a set of 1528make targets: `make jdk.crypto.cryptoki jdk.crypto.ec jdk.crypto.mscapi` 1529 1530#### Building Individual Module Phases 1531 1532The build process for each module is divided into separate phases. Not all 1533modules need all phases. Which are needed depends on what kind of source code 1534and other artifact the module consists of. The phases are: 1535 1536 * `gensrc` (Generate source code to compile) 1537 * `gendata` (Generate non-source code artifacts) 1538 * `copy` (Copy resource artifacts) 1539 * `java` (Compile Java code) 1540 * `launchers` (Compile native executables) 1541 * `libs` (Compile native libraries) 1542 1543You can build only a single phase for a module by using the notation 1544`$MODULE-$PHASE`. For instance, to build the `gensrc` phase for `java.base`, 1545use `make java.base-gensrc`. 1546 1547Note that some phases may depend on others, e.g. `java` depends on `gensrc` (if 1548present). Make will build all needed prerequisites before building the 1549requested phase. 1550 1551#### Skipping the Dependency Check 1552 1553When using an iterative development style with frequent quick rebuilds, the 1554dependency check made by make can take up a significant portion of the time 1555spent on the rebuild. In such cases, it can be useful to bypass the dependency 1556check in make. 1557 1558> **Note that if used incorrectly, this can lead to a broken build!** 1559 1560To achieve this, append `-only` to the build target. For instance, `make 1561jdk.jdwp.agent-java-only` will *only* build the `java` phase of the 1562`jdk.jdwp.agent` module. If the required dependencies are not present, the 1563build can fail. On the other hand, the execution time measures in milliseconds. 1564 1565A useful pattern is to build the first time normally (e.g. `make 1566jdk.jdwp.agent`) and then on subsequent builds, use the `-only` make target. 1567 1568#### Rebuilding Part of java.base (JDK\_FILTER) 1569 1570If you are modifying files in `java.base`, which is the by far largest module 1571in the JDK, then you need to rebuild all those files whenever a single file has 1572changed. (This inefficiency will hopefully be addressed in JDK 10.) 1573 1574As a hack, you can use the make control variable `JDK_FILTER` to specify a 1575pattern that will be used to limit the set of files being recompiled. For 1576instance, `make java.base JDK_FILTER=javax/crypto` (or, to combine methods, 1577`make java.base-java-only JDK_FILTER=javax/crypto`) will limit the compilation 1578to files in the `javax.crypto` package. 1579 1580## Understanding the Build System 1581 1582This section will give you a more technical description on the details of the 1583build system. 1584 1585### Configurations 1586 1587The build system expects to find one or more configuration. These are 1588technically defined by the `spec.gmk` in a subdirectory to the `build` 1589subdirectory. The `spec.gmk` file is generated by `configure`, and contains in 1590principle the configuration (directly or by files included by `spec.gmk`). 1591 1592You can, in fact, select a configuration to build by pointing to the `spec.gmk` 1593file with the `SPEC` make control variable, e.g. `make SPEC=$BUILD/spec.gmk`. 1594While this is not the recommended way to call `make` as a user, it is what is 1595used under the hood by the build system. 1596 1597### Build Output Structure 1598 1599The build output for a configuration will end up in `build/<configuration 1600name>`, which we refer to as `$BUILD` in this document. The `$BUILD` directory 1601contains the following important directories: 1602 1603``` 1604buildtools/ 1605configure-support/ 1606hotspot/ 1607images/ 1608jdk/ 1609make-support/ 1610support/ 1611test-results/ 1612test-support/ 1613``` 1614 1615This is what they are used for: 1616 1617 * `images`: This is the directory were the output of the `*-image` make 1618 targets end up. For instance, `make jdk-image` ends up in `images/jdk`. 1619 1620 * `jdk`: This is the "exploded image". After `make jdk`, you will be able to 1621 launch the newly built JDK by running `$BUILD/jdk/bin/java`. 1622 1623 * `test-results`: This directory contains the results from running tests. 1624 1625 * `support`: This is an area for intermediate files needed during the build, 1626 e.g. generated source code, object files and class files. Some noteworthy 1627 directories in `support` is `gensrc`, which contains the generated source 1628 code, and the `modules_*` directories, which contains the files in a 1629 per-module hierarchy that will later be collapsed into the `jdk` directory 1630 of the exploded image. 1631 1632 * `buildtools`: This is an area for tools compiled for the build platform 1633 that are used during the rest of the build. 1634 1635 * `hotspot`: This is an area for intermediate files needed when building 1636 hotspot. 1637 1638 * `configure-support`, `make-support` and `test-support`: These directories 1639 contain files that are needed by the build system for `configure`, `make` 1640 and for running tests. 1641 1642### Fixpath 1643 1644Windows path typically look like `C:\User\foo`, while Unix paths look like 1645`/home/foo`. Tools with roots from Unix often experience issues related to this 1646mismatch when running on Windows. 1647 1648In the JDK build, we always use Unix paths internally, and only just before 1649calling a tool that does not understand Unix paths do we convert them to 1650Windows paths. 1651 1652This conversion is done by the `fixpath` tool, which is a small wrapper that 1653modifies unix-style paths to Windows-style paths in command lines. Fixpath is 1654compiled automatically by `configure`. 1655 1656### Native Debug Symbols 1657 1658Native libraries and executables can have debug symbol (and other debug 1659information) associated with them. How this works is very much platform 1660dependent, but a common problem is that debug symbol information takes a lot of 1661disk space, but is rarely needed by the end user. 1662 1663The JDK supports different methods on how to handle debug symbols. The 1664method used is selected by `--with-native-debug-symbols`, and available methods 1665are `none`, `internal`, `external`, `zipped`. 1666 1667 * `none` means that no debug symbols will be generated during the build. 1668 1669 * `internal` means that debug symbols will be generated during the build, and 1670 they will be stored in the generated binary. 1671 1672 * `external` means that debug symbols will be generated during the build, and 1673 after the compilation, they will be moved into a separate `.debuginfo` file. 1674 (This was previously known as FDS, Full Debug Symbols). 1675 1676 * `zipped` is like `external`, but the .debuginfo file will also be zipped 1677 into a `.diz` file. 1678 1679When building for distribution, `zipped` is a good solution. Binaries built 1680with `internal` is suitable for use by developers, since they facilitate 1681debugging, but should be stripped before distributed to end users. 1682 1683### Autoconf Details 1684 1685The `configure` script is based on the autoconf framework, but in some details 1686deviate from a normal autoconf `configure` script. 1687 1688The `configure` script in the top level directory of the JDK is just a thin 1689wrapper that calls `make/autoconf/configure`. This in turn will run `autoconf` 1690to create the runnable (generated) configure script, as 1691`.build/generated-configure.sh`. Apart from being responsible for the 1692generation of the runnable script, the `configure` script also provides 1693functionality that is not easily expressed in the normal Autoconf framework. As 1694part of this functionality, the generated script is called. 1695 1696The build system will detect if the Autoconf source files have changed, and 1697will trigger a regeneration of the generated script if needed. You can also 1698manually request such an update by `bash configure autogen`. 1699 1700In previous versions of the JDK, the generated script was checked in at 1701`make/autoconf/generated-configure.sh`. This is no longer the case. 1702 1703### Developing the Build System Itself 1704 1705This section contains a few remarks about how to develop for the build system 1706itself. It is not relevant if you are only making changes in the product source 1707code. 1708 1709While technically using `make`, the make source files of the JDK does not 1710resemble most other Makefiles. Instead of listing specific targets and actions 1711(perhaps using patterns), the basic modus operandi is to call a high-level 1712function (or properly, macro) from the API in `make/common`. For instance, to 1713compile all classes in the `jdk.internal.foo` package in the `jdk.foo` module, 1714a call like this would be made: 1715 1716``` 1717$(eval $(call SetupJavaCompilation, BUILD_FOO_CLASSES, \ 1718 SETUP := GENERATE_OLDBYTECODE, \ 1719 SRC := $(TOPDIR)/src/jkd.foo/share/classes, \ 1720 INCLUDES := jdk/internal/foo, \ 1721 BIN := $(SUPPORT_OUTPUTDIR)/foo_classes, \ 1722)) 1723``` 1724 1725By encapsulating and expressing the high-level knowledge of *what* should be 1726done, rather than *how* it should be done (as is normal in Makefiles), we can 1727build a much more powerful and flexible build system. 1728 1729Correct dependency tracking is paramount. Sloppy dependency tracking will lead 1730to improper parallelization, or worse, race conditions. 1731 1732To test for/debug race conditions, try running `make JOBS=1` and `make 1733JOBS=100` and see if it makes any difference. (It shouldn't). 1734 1735To compare the output of two different builds and see if, and how, they differ, 1736run `$BUILD1/compare.sh -o $BUILD2`, where `$BUILD1` and `$BUILD2` are the two 1737builds you want to compare. 1738 1739To automatically build two consecutive versions and compare them, use 1740`COMPARE_BUILD`. The value of `COMPARE_BUILD` is a set of variable=value 1741assignments, like this: 1742``` 1743make COMPARE_BUILD=CONF=--enable-new-hotspot-feature:MAKE=hotspot 1744``` 1745See `make/InitSupport.gmk` for details on how to use `COMPARE_BUILD`. 1746 1747To analyze build performance, run with `LOG=trace` and check `$BUILD/build-trace-time.log`. 1748Use `JOBS=1` to avoid parallelism. 1749 1750Please check that you adhere to the [Code Conventions for the Build System]( 1751http://openjdk.java.net/groups/build/doc/code-conventions.html) before 1752submitting patches. 1753 1754## Contributing to the JDK 1755 1756So, now you've built your JDK, and made your first patch, and want to 1757contribute it back to the OpenJDK Community. 1758 1759First of all: Thank you! We gladly welcome your contribution. 1760However, please bear in mind that the JDK is a massive project, and we must ask 1761you to follow our rules and guidelines to be able to accept your contribution. 1762 1763The official place to start is the ['How to contribute' page]( 1764http://openjdk.java.net/contribute/). There is also an official (but somewhat 1765outdated and skimpy on details) [Developer's Guide]( 1766http://openjdk.java.net/guide/). 1767 1768If this seems overwhelming to you, the Adoption Group is there to help you! A 1769good place to start is their ['New Contributor' page]( 1770https://wiki.openjdk.java.net/display/Adoption/New+Contributor), or start 1771reading the comprehensive [Getting Started Kit]( 1772https://adoptopenjdk.gitbooks.io/adoptopenjdk-getting-started-kit/en/). The 1773Adoption Group will also happily answer any questions you have about 1774contributing. Contact them by [mail]( 1775http://mail.openjdk.java.net/mailman/listinfo/adoption-discuss) or [IRC]( 1776http://openjdk.java.net/irc/). 1777 1778--- 1779# Override styles from the base CSS file that are not ideal for this document. 1780header-includes: 1781 - '<style type="text/css">pre, code, tt { color: #1d6ae5; }</style>' 1782--- 1783