### Question:
TableStoreUtils { static boolean hasRKey(ByteString rKey) { return null != rKey && rKey.size() > 0; }    }### Answer:
@Test public void testHasRKey() { assertFalse(hasRKey(null)); assertFalse(hasRKey(ByteString.copyFrom(new byte[0]))); assertTrue(hasRKey(ByteString.copyFromUtf8("test"))); }