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23 
24 /**
25  * @test
26  * @bug 8003280
27  * @summary Add lambda tests
28  *   Test bridge methods in certain SAM conversion
29  * @compile BridgeMethod.java
30  * @run main BridgeMethod
31  */
32 
33 import java.lang.reflect.Method;
34 import java.util.HashSet;
35 import java.util.Set;
36 
37 public class BridgeMethod {
38 
m()39     interface H {Object m();}
40 
m(T t)41     interface K<T> {void m(T t);}
42 
43     interface L extends K<String> {} //generic substitution
44 
m(String s)45     interface M {void m(String s);}
46 
47     interface KM extends K<String>, M{} //generic substitution
48 
m()49     interface N extends H {String m();} //covariant return
50 
assertTrue(boolean cond)51     private static void assertTrue(boolean cond) {
52         if (!cond)
53             throw new AssertionError();
54     }
55 
bar(String s)56     static void bar(String s) {
57         System.out.println("BridgeMethod.bar(String) " + s);
58     }
59 
moo()60     String moo() {
61         return "moo";
62     }
63 
setOfStringObject()64     private static Set<String> setOfStringObject() {
65         Set<String> s = new HashSet<>();
66         s.add("java.lang.String");
67         s.add("java.lang.Object");
68         return s;
69     }
70 
main(String[] args)71     public static void main(String[] args) {
72         L la = BridgeMethod::bar; //static reference
73         la.m("hi");
74         Class<? extends L> c1 = la.getClass();
75         Method[] methods = c1.getDeclaredMethods();
76         Set<String> types = setOfStringObject();
77         System.out.println("methods in SAM conversion of L:");
78         for(Method m : methods) {
79             System.out.println(m.toGenericString());
80             assertTrue(m.getName().equals("m"));
81             Class[] parameterTypes = m.getParameterTypes();
82             assertTrue(parameterTypes.length == 1);
83             assertTrue(types.remove(parameterTypes[0].getName()));
84         }
85         assertTrue(types.isEmpty() || (types.size() == 1 && types.contains("java.lang.String")));
86 
87         KM km = BridgeMethod::bar;
88         //km.m("hi"); //will be uncommented when CR7028808 fixed
89         Class<? extends KM> c2 = km.getClass();
90         methods = c2.getDeclaredMethods();
91         types = setOfStringObject();
92         System.out.println("methods in SAM conversion of KM:");
93         for(Method m : methods) {
94             System.out.println(m.toGenericString());
95             assertTrue(m.getName().equals("m"));
96             Class<?>[] parameterTypes = m.getParameterTypes();
97             assertTrue(parameterTypes.length == 1);
98             assertTrue(types.remove(parameterTypes[0].getName()));
99         }
100         assertTrue(types.isEmpty());
101 
102         N n = new BridgeMethod()::moo; //instance reference
103         assertTrue( n.m().equals("moo") );
104         assertTrue( ((H)n).m().equals("moo") );
105         Class<? extends N> c3 = n.getClass();
106         methods = c3.getDeclaredMethods();
107         types = setOfStringObject();
108         System.out.println("methods in SAM conversion of N:");
109         for(Method m : methods) {
110             System.out.println(m.toGenericString());
111             if (m.getName().equals("m")) {
112                 Class<?> returnType = m.getReturnType();
113                 assertTrue(types.remove(returnType.getName()));
114             }
115         }
116         assertTrue(types.size() == 1); //there's a bridge
117     }
118 }
119