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23 
24 /**
25  * @test
26  * @bug 8003280
27  * @summary Add lambda tests
28  *   This test is for lambda expressions
29  * @compile LambdaTest1.java
30  * @run main LambdaTest1
31  */
32 
33 import java.util.Collections;
34 import java.util.List;
35 import java.util.ArrayList;
36 
37 public class LambdaTest1 {
main(String[] args)38     public static void main(String[] args) {
39 
40         LambdaTest1 test = new LambdaTest1();
41 
42         test.method2((int n) -> { });
43         test.method2((int n) -> { });
44         test.method2((int n) -> { return; }); // ";" is mandatory here
45         test.method2((int n) -> { System.out.println(n); }); // ";" is optional here
46         test.method2(n -> { System.out.println(n); }); //warning, explict type required for n?
47 
48         test.method3(()-> { System.out.println("implementing VoidVoid.vvMethod()"); });
49         test.method3(() -> {});
50 
51         test.method4(()-> 42);
52         test.method4(()-> { return 42; });//";" is mandatory here
53 
54         test.method5((int n)-> n+1);
55         test.method5((int n) -> 42);
56         test.method5((int n) -> { return 42; });
57         test.method5(
58             (int n) -> { //"{" optional here
59                 if(n > 0)
60                     return n++;
61                 else
62                     return n--;
63             }
64         );
65 
66         Runnable r = ()-> { System.out.println("Runnable.run() method implemented"); };
67         r.run();
68         ((Runnable)()-> { System.out.println("Runnable.run() method implemented"); }).run();
69     }
70 
method2(VoidInt a)71     void method2(VoidInt a) {
72         System.out.println("method2()");
73         final int N = 1;
74         int n = 2; //effectively final variable
75         System.out.println("method2() \"this\":" + this);
76         ((Runnable)
77             ()->{
78                 System.out.println("inside lambda \"this\":" + this);
79                 System.out.println("inside lambda accessing final variable N:" + N);
80                 System.out.println("inside lambda accessing effectively final variable n:" + n);
81             }
82         ).run();
83         //n++; //compile error if n is modified
84         a.viMethod(2);
85     }
86 
method3(VoidVoid a)87     void method3(VoidVoid a) {
88         System.out.println("method3()");
89         a.vvMethod();
90     }
91 
method4(IntVoid a)92     void method4(IntVoid a) {
93         System.out.println("method4()");
94         System.out.println(a.ivMethod());
95     }
96 
method5(IntInt a)97     void method5(IntInt a) {
98         System.out.println("method5()");
99         System.out.println(a.iiMethod(5));
100     }
101 
102 
103     //SAM type interfaces
104     interface VoidInt {
viMethod(int n)105         void viMethod(int n);
106     }
107 
108     interface VoidVoid {
vvMethod()109         void vvMethod();
110     }
111 
112     interface IntVoid {
ivMethod()113         int ivMethod();
114     }
115 
116     interface IntInt {
iiMethod(int n)117         int iiMethod(int n);
118     }
119 }
120