### Question:
KeyStringValueItem implements KeyValueItem<K, String> { @Override public boolean equals(Object other) { if (this == other) { return true; } if (!(other instanceof KeyStringValueItem)) { return false; } KeyStringValueItem<?> item = (KeyStringValueItem<?>) other; return new EqualsBuilder().append(key, item.getKey()).isEquals(); } protected  KeyStringValueItem(K key, String value); @Override K getKey(); @Override String getValue(); static KeyStringValueItem<K> keyEmptyValue(K key); static KeyStringValueItem<K> keyValue(K key, String value); @Override String toString(); @Override int hashCode(); @Override boolean equals(Object other);  }### Answer:
@Test public void testEquals() { KeyStringValueItem<String> eq1 = new KeyStringValueItem<>("A", "Chuck"); KeyStringValueItem<String> eq2 = new KeyStringValueItem<>("A", "Norris"); KeyStringValueItem<String> eq3 = new KeyStringValueItem<>("A", "Roundhouse"); KeyStringValueItem<String> diff = new KeyStringValueItem<>("B", "Rambo"); TestUtils.testEqualsAndHashCodes(eq1, eq2, eq3, diff); }