### Question:
Solution implements Expirable { @Override public boolean equals(Object other) { return this == other || (other instanceof Solution && equals(this, ((Solution<V>) other))); } Solution(V[] values, long expirationTime, Index<Solution<V>> expirationIndex);  Solution(V[] values, Index<Solution<V>> expirationIndex); V[] getValues(); @Override long getExpirationTime(); @Override void expire(); @Override boolean isExpired(); int compareByExpirationTime(Solution<V> other); @Override int hashCode(); @Override boolean equals(Object other);  }### Answer:
@Test public void testSolutionSets() { Solution<String> s1, s2; long expTime = StreamProcessor.NEVER_EXPIRE; s1 = newSolution(new String[]{}, expTime); s2 = newSolution(new String[]{}, expTime); assertTrue(s1.equals(s1)); assertTrue(s1.equals(s2)); s2 = newSolution(new String[]{"v1"}, expTime); assertTrue(s2.equals(s2)); assertFalse(s1.equals(s2)); s1 = newSolution(new String[]{"v2"}, expTime); assertFalse(s1.equals(s2)); s1 = newSolution(new String[]{"v1", "v2"}, expTime); assertFalse(s1.equals(s2)); s2 = newSolution(new String[]{"v1", "v2"}, expTime); assertTrue(s1.equals(s2)); s2 = newSolution(new String[]{"v1", "v3"}, expTime); assertFalse(s1.equals(s2)); }