### Question:
MutableInt extends Number implements Comparable<MutableInt>, Mutable<Number> { @Override public int hashCode() { return Integer.hashCode(value); } MutableInt();  MutableInt(int value);  MutableInt(Number value);  MutableInt(String value); @Override Integer getValue(); @Override void setValue(Number value); void setValue(int value); @Override int compareTo(MutableInt anotherInteger); @Override int intValue(); @Override long longValue(); @Override float floatValue(); @Override double doubleValue(); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString(); final int getAndIncrement(); final int getAndDecrement(); final int getAndAdd(int delta); final int incrementAndGet(); final int decrementAndGet(); final int addAndGet(int delta);  }### Answer:
@Test public void testHashCode() { MutableInt i = new MutableInt(1); assertTrue(i.hashCode() == 1); }