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25 
26 /* @test
27  * @summary unit tests for java.lang.invoke.MethodHandles
28  * @run testng/othervm -ea -esa test.java.lang.invoke.ConstantIdentityMHTest
29  */
30 package test.java.lang.invoke;
31 
32 import java.lang.invoke.MethodHandle;
33 import java.lang.invoke.MethodHandles;
34 import java.lang.invoke.MethodType;
35 import java.util.List;
36 import static java.lang.invoke.MethodHandles.*;
37 import static java.lang.invoke.MethodType.*;
38 import static org.testng.AssertJUnit.*;
39 import org.testng.annotations.*;
40 
41 public class ConstantIdentityMHTest {
42 
43     @DataProvider(name = "testZeroData")
testZeroData()44     private Object[][] testZeroData() {
45        return new Object[][] {
46            {void.class, "()void"},
47            {int.class, "()int"},
48            {byte.class, "()byte"},
49            {short.class, "()short"},
50            {long.class, "()long"},
51            {float.class, "()float"},
52            {double.class, "()double"},
53            {boolean.class, "()boolean"},
54            {char.class, "()char"},
55            {Integer.class, "()Integer"}
56        };
57     }
58 
59     @Test(dataProvider = "testZeroData")
testZero(Class<?> expectedtype, String expected)60     public void testZero(Class<?> expectedtype, String expected) throws Throwable {
61         assertEquals(MethodHandles.zero(expectedtype).type().toString(), expected);
62     }
63 
64     @Test
65     @ExpectedExceptions(NullPointerException.class)
testZeroNPE()66     public void testZeroNPE() {
67         MethodHandle mh = MethodHandles.zero(null);
68     }
69 
70     @Test
testEmpty()71     void testEmpty() throws Throwable {
72         MethodHandle cat = lookup().findVirtual(String.class, "concat", methodType(String.class, String.class));
73         assertEquals("xy", (String)cat.invoke("x","y"));
74         MethodHandle mhEmpty = MethodHandles.empty(cat.type());
75         assertEquals(null, (String)mhEmpty.invoke("x","y"));
76     }
77 
78     @Test
79     @ExpectedExceptions(NullPointerException.class)
testEmptyNPE()80     void testEmptyNPE() {
81         MethodHandle lenEmptyMH = MethodHandles.empty(null);
82     }
83 }
84