enemies.add("Dave");
    assertEquals(1, goodFriends.size());
    assertEquals(2, immut.size());
    assertEquals(2, mut.size());
  }

  public void testSymmetricDifference() {
    Set<String> friends = Sets.newHashSet("Tom", "Joe", "Dave");
    Set<String> enemies = Sets.newHashSet("Dick", "Harry", "Tom");

      @Override
      public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (disallowedClassNames.contains(name)) {
          throw new ClassNotFoundException("I'm sorry Dave, I'm afraid I can't do that.");
        }
        if (name.startsWith(concurrentPackage)) {
          Class<?> c = findLoadedClass(name);
          if (c == null) {
            return super.findClass(name);

         * problems can exist with methods like FutureTask.done(), not to mention slow calls to
         * Thread.interrupt() (as discussed in InterruptibleTask). At the end of the day, it's
         * unlikely that cancel() will be slow, so we can probably get away with calling it while
         * holding a lock. Still, it would be nice to avoid somehow.
         */
        lock.lock();
        try {

      @Override
      public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (blocklist.contains(name)) {
          throw new ClassNotFoundException("I'm sorry Dave, I'm afraid I can't do that.");
        }
        if (name.startsWith(concurrentPackage)) {
          Class<?> c = findLoadedClass(name);
          if (c == null) {
            return super.findClass(name);

  `And how many hours a day did you do lessons?' said Alice, in a
hurry to change the subject.

  `Ten hours the first day,' said the Mock Turtle: `nine the
next, and so on.'

  `What a curious plan!' exclaimed Alice.

  `That's the reason they're called lessons,' the Gryphon
remarked:  `because they lessen from day to day.'

as???g&orf?ujb??i&dnaort?vnarg??kob?ladendua?maherk&a?å??n&it?urgsrop??orf-&dron?r&os?øs???r&aieb?evats??sfev?uaks?yrts??o&6axi-ygvtsev--nx?c,d&ob?rav??ievs?kssouf?l&m&ob?øb??ous&adna?ech&ac?áč???so!.sg???msdeks?niekotuak?r&egark?olf?y&oso?øso???s&dav?mort???p&ed?ohsdaerpsym,p&akdron?elk???r&a&d&dj&ab?áb??iab??jtif?luag?mah?vsyt??e&gn&a&k&iel?ro??merb?n&at?mas??rav-r&os?øs??srop?talf?v&ats?el??y&oh?øh???ivsgnok??il?jkniets?k&a&nvej?rem?s&gnir?nellu???ie-er&den?v&o?ø???ram?sa?årem??la&jf?vh??m&b&...

      @Override
      public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (disallowedClassNames.contains(name)) {
          throw new ClassNotFoundException("I'm sorry Dave, I'm afraid I can't do that.");
        }
        if (name.startsWith(concurrentPackage)) {
          Class<?> c = findLoadedClass(name);
          if (c == null) {
            return super.findClass(name);

      @Override
      public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (blocklist.contains(name)) {
          throw new ClassNotFoundException("I'm sorry Dave, I'm afraid I can't do that.");
        }
        if (name.startsWith(concurrentPackage)) {
          Class<?> c = findLoadedClass(name);
          if (c == null) {
            return super.findClass(name);

  `And how many hours a day did you do lessons?' said Alice, in a
hurry to change the subject.

  `Ten hours the first day,' said the Mock Turtle: `nine the
next, and so on.'

  `What a curious plan!' exclaimed Alice.

  `That's the reason they're called lessons,' the Gryphon
remarked:  `because they lessen from day to day.'

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());
    assertEquals(2, immut.size());
    assertEquals(2, mut.size());
  }

  public void testSymmetricDifference() {
    Set<String> friends = Sets.newHashSet("Tom", "Joe", "Dave");
    Set<String> enemies = Sets.newHashSet("Dick", "Harry", "Tom");