/**
 * A callback for accepting the results of a {@link java.util.concurrent.Future} computation
 * asynchronously.
 *
 * <p>To attach to a {@link ListenableFuture} use {@link Futures#addCallback}.
 *
 * @author Anthony Zana
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface FutureCallback<V extends @Nullable Object> {
  /** Invoked with the result of the {@code Future} computation when it is successful. */

import java.util.concurrent.Executor;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Test for {@link FutureCallback}.
 *
 * @author Anthony Zana
 */
@GwtCompatible
public class FutureCallbackTest extends TestCase {
  public void testSameThreadSuccess() {
    SettableFuture<String> f = SettableFuture.create();
    MockCallback callback = new MockCallback("foo");