public static BadRequestException appNamespaceAlreadyExists(String appId, String namespaceName) {
    return new BadRequestException("appNamespace already exists for appId:%s namespaceName:%s", appId, namespaceName);
  }
@Test
  public void testAppNamespaceAlreadyExists() {
    BadRequestException appNamespaceAlreadyExists = BadRequestException.appNamespaceAlreadyExists(appId, namespaceName);
    assertEquals("appNamespace already exists for appId:app-1001 namespaceName:application", appNamespaceAlreadyExists.getMessage());
  }