### Question:
IsEqual implements BinaryPredicate<L, R> { public static <L, R> IsEqual<L, R> instance() { return new IsEqual<L, R>(); } IsEqual(); boolean test(L left, R right); @Override boolean equals(Object that); @Override int hashCode(); @Override String toString(); static IsEqual<L, R> instance(); static Predicate<L> to(R object); static final IsEqual<Object, Object> INSTANCE; }### Answer:
@Test public void testConstant() throws Exception { assertEquals(IsEqual.instance(), IsEqual.instance()); assertNotSame(IsEqual.instance(), IsEqual.instance()); assertSame(IsEqual.INSTANCE, IsEqual.INSTANCE); }