### Question:
FileSerializedObjectCache implements IObjectCache { public boolean exists(String[] key) throws ApplicationException { if (key == null || key.length == 0) { throw new ApplicationException("null or empty object key"); } String filename = getFilename(key); File file = new File(filename); return file.exists(); } FileSerializedObjectCache(String cacheDir, boolean zipEnabled);  FileSerializedObjectCache(String cacheDir); String getCacheDir(); String getFilename(String [] key); String getSubdirname(String [] key, int len); void putObject(String subdir, String key, Object value); void put(String [] key, Object value, boolean isVolatile); Object get(String [] key, boolean isVolatile); void remove(String [] key); boolean exists(String[] key); List<String[]> list(String[] key);  }### Answer:
@Test public void testExists() throws Exception { IObjectCache cache = new FileSerializedObjectCache(tempDir.getTempDir()); String [] key = {"A", "B.txt"}; cache.put(key, key, true); assertFalse(cache.exists(new String[] {"C"})); assertFalse(cache.exists(new String[] {"A", "C.txt"})); assertTrue(cache.exists(key)); }