### Question:
Endpoint implements Copiable<Endpoint>, Serializable { @Override public String toString() { if (str == null) { str = this.ip + ":" + this.port; } return str; } Endpoint();  Endpoint(String address, int port); String getIp(); int getPort(); @Override String toString(); @Override Endpoint copy(); @Override int hashCode(); @Override boolean equals(Object obj);  }### Answer:
@Test public void testToStringReset() { final Endpoint ep = new Endpoint("192.168.1.1", 8080); assertEquals("192.168.1.1:8080", ep.toString()); assertEquals("192.168.1.1:8080", ep.toString()); }