### Question:
IntervalImpl extends JObject implements Interval<T>, JCloneable<Interval<T>> { @Override public boolean contains(@Nonnull T value) { return this.left.isLowerOrEqualsThan(value) && this.right.isHigherOrEqualsThan(value); } @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = {"NP_NONNULL_FIELD_NOT_INITIALIZED_IN_CONSTRUCTOR"}) protected  IntervalImpl(); private  IntervalImpl(@Nonnull IntervalLimit<T> left,
						 @Nonnull IntervalLimit<T> right); @Nullable T getLeftLimit(); @Nullable T getRightLimit(); @Nonnull @Override IntervalLimit<T> getRight(); @Nonnull @Override IntervalLimit<T> getLeft(); @Override boolean contains(@Nonnull T value); @Override boolean contains(@Nonnull Interval<T> that); @Override boolean isClosed(); @Override boolean isInfinite(); @Override boolean isHalfClosed(); @Nonnull @Override IntervalImpl<T> clone(); @Override String toString(); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void testContains() throws Exception { final Interval<Integer> interval1 = Intervals.newClosedInterval(10, 20); final Interval<Integer> interval2 = Intervals.newClosedInterval(12, 19); Assert.assertTrue(interval1.contains(interval2)); }