Does Java 8 Support Closures?

Question

I\'m confused. I thought Java 8 was going to emerge from the stone age and start supporting lambdas/closures. But when I try this:

public static void main(St         


        

Answer 1

You can use final references to get around altering state of variables declared in an outer scope, but the result remains the same, the state of the closures outer scope is not kept and further alterations to the object referenced to (by a final reference) are seen in the closure.

@Test
public void clojureStateSnapshotTest() {
    Function wrapperFunc;
    wrapperFunc = (a) -> {
        // final reference
        final WrapLong outerScopeState = new WrapLong();

        outerScopeState.aLong = System.currentTimeMillis();
        System.out.println("outer scope state BEFORE: " + outerScopeState.aLong);

        Function closure = (b) -> {
            System.out.println("closure: " + outerScopeState.aLong);
            return b;
        };

        outerScopeState.aLong = System.currentTimeMillis();
        System.out.println("outer scope state AFTER: " + outerScopeState.aLong);

        // show correct snapshot state
        closure.apply(new Object());

        return a;
    };
    // init clojure
    wrapperFunc.apply(new Object());
}

public class WrapLong {
    public long aLong = 0;
}

but still fun...