### Question:
RowId implements Serializable { @Override public String toString() { if (getId() == null) { return ""; } StringBuilder builder = new StringBuilder(); for (Object id : getId()) { builder.append(id); builder.append('/'); } if (builder.length() > 0) { return builder.substring(0, builder.length() - 1); } return builder.toString(); } protected  RowId();  RowId(Object... id); Object[] getId(); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void toString_defaultCtor_noException() { RowId rowId = new RowId(); Assert.assertTrue("Unexpected to string for empty Row Id", rowId .toString().isEmpty()); }