Why is the stream closed when using RestTemplate to retrieve a resource with 9xx status code?

Question

I have a REST endpoint in my Spring Boot application (version 1.5.9.RELEASE) with the following signature:

@RequestMapping(value = "/users", method = RequestMethod.POST) throws UsernameExistsException, EmailExistsException
public UserProxy addUser(@RequestBody UserProxy userProxy) {
  ...
}

The exceptions are handled by an @ExceptionHandler annotated method in a @ControllerAdvice annotated class:

@EnableWebMvc
@ControllerAdvice
public class ControllerExceptionHandler {

  @ExceptionHandler(EmailExistsException.class)
  public ResponseEntity<String> handleEmailExistsException() {
    return ResponseEntity
            .status(UsersStatusCodes.EMAIL_EXISTS) // status code 912
            .body("Email already exists");
  }

  @ExceptionHandler(UsernameExistsException.class)
  public ResponseEntity<String> handleUsernameExistsException() {
    return ResponseEntity
            .status(UsersStatusCodes.USERNAME_EXISTS) // status code 911
            .body("Username already exists");
  }
}

However, when the endpoint is accessed and an exception is thrown, I retrieve the following exception on the client side:

org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://192.168.99.100:8080/users": stream is closed; nested exception is java.io.IOException: stream is closed
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:673)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:620)
at org.springframework.web.client.RestTemplate.postForObject(RestTemplate.java:387)
at com.cheetahrunner.users.mongo.client.UsersClient.createUser(UsersClient.java:44)
at com.cheetahrunner.users.UsersServiceTest.addUser(UsersServiceTest.java:102)
at com.cheetahrunner.users.UsersServiceTest.testAddRemoveUser(UsersServiceTest.java:47)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
15:37:44.517 [main] DEBUG org.springframework.web.client.RestTemplate - POST request for "http://192.168.99.100:8080/users" resulted in 911 (null)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:283)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:173)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:128)
    at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:203)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:155)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
Caused by: java.io.IOException: stream is closed
    at java.base/sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.ensureOpen(HttpURLConnection.java:3417)
    at java.base/sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(HttpURLConnection.java:3422)
    at java.base/java.io.FilterInputStream.read(FilterInputStream.java:83)
    at java.base/java.io.PushbackInputStream.read(PushbackInputStream.java:136)
    at org.springframework.web.client.MessageBodyClientHttpResponseWrapper.hasEmptyMessageBody(MessageBodyClientHttpResponseWrapper.java:102)
    at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:82)
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:662)
    ... 30 more

The code used to access the endpoint is the following:

rest.exchange(host + "/users", HttpMethod.POST, new HttpEntity<UserProxy>(user), UserProxy.class)

I got no idea what could cause the problem, does anyone have a hint for me?

The endpoint is reachable via Postman, where 911 response with status text "Username already exists" is received.

Are you sure that you specify POST method as parameter? From your stack trace: I/O error on PUT request — Andrew Nepogoda, Dec 21 '17 at 14:35
Sorry the stack trace is actually from a PUT method where I experience exactly the same error — user2035039, Dec 21 '17 at 14:36
Because then I would need `instanceof` to differentiate between different types of exceptions, which is a bad pattern in my opinion. Also, the exception happens on the client side, so the exception handling on the server side should be fine. — user2035039, Dec 21 '17 at 14:43
check this question https://stackoverflow.com/questions/11648706/spring-resttemplate-client-connection-refused-exception — Andrew Nepogoda, Dec 21 '17 at 14:56
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/161739/discussion-between-andrew-nepogoda-and-user2035039). — Andrew Nepogoda, Dec 21 '17 at 14:58

score 0 · Answer 1 · answered Dec 21 '17 at 15:24

Implement org.springframework.web.client.ResponseErrorHandler and set it to your rest template:

rest.setErrorHandler(errorHandler);

ResponseErrorHandler has 2 methods:

/**
     * Indicate whether the given response has any errors.
     * <p>Implementations will typically inspect the
     * {@link ClientHttpResponse#getStatusCode() HttpStatus} of the response.
     * @param response the response to inspect
     * @return {@code true} if the response has an error; {@code false} otherwise
     * @throws IOException in case of I/O errors
     */
    boolean hasError(ClientHttpResponse response) throws IOException;

    /**
     * Handle the error in the given response.
     * <p>This method is only called when {@link #hasError(ClientHttpResponse)}
     * has returned {@code true}.
     * @param response the response with the error
     * @throws IOException in case of I/O errors
     */
    void handleError(ClientHttpResponse response) throws IOException;

In the second one you should implement error handling logic.

The first one should be like:

@Override
public boolean hasError(ClientHttpResponse response) throws IOException {
    HttpStatus code = response.getStatusCode();
    return code != HttpStatus.OK && code != HttpStatus.NO_CONTENT && code != HttpStatus.NOT_MODIFIED;
}

score 0 · Answer 2 · answered Jan 10 '18 at 11:17

I experienced the same issue (with the same version of Spring Boot) and to fix it I removed the content and set a content length header of 0:

@ExceptionHandler(NotFoundException.class)
public ResponseEntity<Object> applicationFormNotFound() {
    final HttpHeaders headers = new HttpHeaders();
    headers.add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE);
    headers.add(HttpHeaders.CONTENT_LENGTH, "0");
    return ResponseEntity.status(HttpStatus.NOT_FOUND)
            .headers(headers)
            .build();
}

Admittedly this is not much help if you actually need to send content!

Why is the stream closed when using RestTemplate to retrieve a resource with 9xx status code?

2 Answers2