public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(ImmutableMap.class);
    tester.testAllPublicInstanceMethods(new ImmutableMap.Builder<Object, Object>());
    tester.testAllPublicInstanceMethods(ImmutableMap.of());
    tester.testAllPublicInstanceMethods(ImmutableMap.of("one", 1));
    tester.testAllPublicInstanceMethods(ImmutableMap.of("one", 1, "two", 2, "three", 3));