### Question:
JibSystemProperties { public static boolean skipExistingImages() { return Boolean.getBoolean(SKIP_EXISTING_IMAGES); } private  JibSystemProperties(); static int getHttpTimeout(); static boolean useCrossRepositoryBlobMounts(); static boolean serializeExecution(); static boolean sendCredentialsOverHttp(); static boolean isUserAgentEnabled(); static void checkHttpTimeoutProperty(); static void checkProxyPortProperty(); static boolean skipExistingImages(); static final String UPSTREAM_CLIENT; @VisibleForTesting static final String HTTP_TIMEOUT; @VisibleForTesting
  static final String SEND_CREDENTIALS_OVER_HTTP; @VisibleForTesting static final String SKIP_EXISTING_IMAGES; }### Answer:
@Test public void testSkipExistingImages_undefined() { System.clearProperty(JibSystemProperties.SKIP_EXISTING_IMAGES); Assert.assertFalse(JibSystemProperties.skipExistingImages()); }