#vulnerable code 
                             @Override
	@SuppressWarnings("unchecked")
	public boolean isInitialized() {

		return requireResponse(vaultOperations.doWithVault(restOperations -> {

			try {
				Map<String, Boolean> body = restOperations.getForObject("sys/init",
						Map.class);

				Assert.state(body != null, "Initialization response must not be null");

				return body.get("initialized");
			}
			catch (HttpStatusCodeException e) {
				throw VaultResponses.buildException(e);
			}
		}));
	} 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                             @Override
	@SuppressWarnings("unchecked")
	public boolean isInitialized() {

		return requireResponse(vaultOperations.doWithSession(restOperations -> {

			try {
				ResponseEntity<Map<String, Boolean>> body = (ResponseEntity) restOperations
						.exchange("sys/init", HttpMethod.GET, emptyNamespace(null),
								Map.class);

				Assert.state(body.getBody() != null,
						"Initialization response must not be null");

				return body.getBody().get("initialized");
			}
			catch (HttpStatusCodeException e) {
				throw VaultResponses.buildException(e);
			}
		}));
	}