### Question:
HopServerStatusCache implements Cache { public static synchronized HopServerStatusCache getInstance() { if ( instance == null ) { instance = new HopServerStatusCache(); } return instance; } private  HopServerStatusCache(); static synchronized HopServerStatusCache getInstance(); void put( String logId, String cacheString, int from ); byte[] get( String logId, int from ); void remove( String id ); @Override Object read( Object key ); @Override Object get( Object key ); @Override void put( Object key, Object value ); @Override void update( Object key, Object value ); @Override void remove( Object key ); @Override void clear(); @Override void destroy(); @Override Map toMap(); @Override void lock( Object key ); @Override void unlock( Object key ); @Override long nextTimestamp(); @Override int getTimeout(); @Override String getRegionName(); @Override long getSizeInMemory(); @Override long getElementCountInMemory(); @Override long getElementCountOnDisk(); static final String HOP_SERVER_STATUS_CACHE; }### Answer:
@Test public void testGetInstance() { Assert.assertTrue( HopServerStatusCache.getInstance() == HopServerStatusCache.getInstance() ); }