Learning Java Lambdas

Example 1

The first example is a simple anonymous class instance passed into our waitFor method.

public class Example1 {
    // anonymous class
    void example() throws InterruptedException {
        waitFor(new Condition() {
            @Override
            public Boolean isSatisfied() {
                return true;
            }
        });
    }
}

If we look at the bytecode below, the thing to notice is that an instance of the anonymous class is newed up at line 6. The #2 refers to a lookup, the result of which is shown in the comment. So it uses the new opcode with whatever is at #2 in the constant pool, this happens to be the anonymous class Example$1.

void example() throws java.lang.InterruptedException; descriptor: ()V flags: Code: stack=3, locals=1, args_size=1 0: new #2 // class Example1$1 3: dup 4: aload_0 5: invokespecial ...