### Question:
MD5HashFileGenerator implements HashFileGenerator, InitializingBean { public int getExpireAfterWrite() { return expireAfterWrite; }  void afterPropertiesSet(); @Override Optional<String> hash(final Optional<URL> url); @Override Optional<String> hashMulti(final Collection<URL> urls); static String getMD5Checksum(final InputStream is); void setHotReloadMode(boolean hotReloadMode); void setCacheMaxSize(int cacheMaxSize); void setExpireAfterWrite(int expireAfterWrite); void setExpireAfterWriteUnit(String expireAfterWriteUnit); boolean isHotReloadMode(); int getCacheMaxSize(); int getExpireAfterWrite(); String getExpireAfterWriteUnit();  }### Answer:
@Test public void testDefaultExpireTime() throws Exception { Assert.assertEquals("default expire in days is 1 day", 1, hashFileGenerator.getExpireAfterWrite()); }