### Question:
LongSparseArray implements Cloneable { public boolean isEmpty() { return size() == 0; } LongSparseArray();  LongSparseArray(int initialCapacity); @Override @SuppressWarnings("unchecked") LongSparseArray<E> clone(); E get(long key); @SuppressWarnings("unchecked") E get(long key, E valueIfKeyNotFound); void delete(long key); void remove(long key); void removeAt(int index); void put(long key, E value); int size(); boolean isEmpty(); long keyAt(int index); @SuppressWarnings("unchecked") E valueAt(int index); void setValueAt(int index, E value); int indexOfKey(long key); int indexOfValue(E value); void clear(); void append(long key, E value); @Override String toString();  }### Answer:
@Test public void isEmpty() throws Exception { LongSparseArray<String> LongSparseArray = new LongSparseArray<>(); assertTrue(LongSparseArray.isEmpty()); for (long i = 0L; i < 5L; i++) { LongSparseArray.put(i, Long.toString(i)); assertFalse(LongSparseArray.isEmpty()); } LongSparseArray.clear(); assertTrue(LongSparseArray.isEmpty()); long key1 = 1L, key2 = 2L; String value1 = "some value", value2 = "some other value"; LongSparseArray.append(key1, value1); assertFalse(LongSparseArray.isEmpty()); LongSparseArray.append(key2, value2); assertFalse(LongSparseArray.isEmpty()); assertFalse(LongSparseArray.isEmpty()); LongSparseArray.remove(key1); assertFalse(LongSparseArray.isEmpty()); LongSparseArray.remove(key2); assertTrue(LongSparseArray.isEmpty()); }