Learning Java Lambdas

Example 3

The Example 3 class uses a Java lambda with our waitFor method. The lambda doesn't do anything other than return true. It's equivalent to example 1.

public class Example3 {
    // simple lambda
    void example() throws InterruptedException {
        waitFor(() -> true);
    }
}

The bytecode is super simple this time. It uses the invokedynamic opcode to create the lambda at line 3 which is then passed to the invokestatic opcode on the next line.

 void example() throws java.lang.InterruptedException;
     Code:
        0: invokedynamic #2, 0 // InvokeDynamic #0:isSatisfied:   
           ()LCondition;
        5: invokestatic #3 // Method WaitFor.waitFor:(LCondition;)V
        8: return

The descriptor for the invokedynamic call is targeting the isSatisfied method on the Condition interface (line 3.). ...