### Question:
SpaceInterceptor implements Space<K,V> { public V rd (K key) { return sp.rd (key); } SpaceInterceptor(Space<K,V> sp); void out(K key, V value); void out(K key, V value, long timeout); void push(K key, V value); void push(K key, V value, long timeout); void put(K key, V value); void put(K key, V value, long timeout); V in(K key); V rd(K key); V in(K key, long timeout); V rd(K key, long timeout); V inp(K key); V rdp(K key); @Override void nrd(K key); @Override V nrd(K key, long timeout); boolean existAny(K[] keys); boolean existAny(K[] keys, long timeout);  }### Answer:
@Test public void testRdThrowsNullPointerException() throws Throwable { SpaceInterceptor spaceInterceptor = new SpaceInterceptor(null); try { spaceInterceptor.rd("", -1L); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot invoke \"org.jpos.space.Space.rd(Object, long)\" because \"this.sp\" is null", ex.getMessage(), "ex.getMessage()"); } assertNull(spaceInterceptor.sp, "spaceInterceptor.sp"); } }