Retrofit: Can't put JAXB to work

[black-snow]

What kind of issue is this?

• [X] Bug report / Question.

I can't get the JaxbConverter to work. I can't tell if I'm missing somethin or if it's broken.
Java 8

build.gradle

implementation 'com.squareup.retrofit2:retrofit:2.5.0'
implementation 'com.squareup.retrofit2:converter-jaxb:2.5.0'

somewhere in the code

Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("https://www.google.com/alerts/feeds/")
            .addConverterFactory(JaxbConverterFactory.create())
            .build();
service = retrofit.create(GoogleAlertService.class);

...

Response<GoogleAlertRssFeed> response = request.execute();
...
LOG.info(response.body().toString());

GoogleAlertRssFeed

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "feed", namespace = "http://www.w3.org/2005/Atom")
public class GoogleAlertRssFeed {

    @XmlElement(required = true)
    public String id;

    public GoogleAlertRssFeed() {
    }

    ...

    @Override
    public String toString() {
        return "GoogleAlertRssFeed{" +
                "id='" + id + '\'' +
            '}';
    }
}

And the XML looks like:

<?xml version="1.0" encoding="utf-8"?> <feed xmlns="http://www.w3.org/2005/Atom" xmlns:idx="urn:atom-extension:indexing"> <id>tag:google.com,2005:reader/user/xyz/state/com.google/alerts/xyz</id> <title>...

But despite the correct raw response the id is always null.

I tried anything I could find on the net.

• Tried @XmlAccessorType(XmlAccessType.FIELD) on the class.
• Tried with / without namespace.
• Tried private field + getter & setter, with/ without @XmlAccessorType(XmlAccessType.FIELD).
• Tried with / without @XmlElement(name = "id").
• Tried adding a constructor that accepts the id.
• Followed the test in the repo.

What am I doing wrong?

Resources:

• https://stackoverflow.com/questions/6768544/jaxb-class-has-two-properties-of-the-same-name
• https://stackoverflow.com/questions/5514752/xml-element-with-attribute-and-content-using-jaxb
• https://stackoverflow.com/questions/49699707/how-to-use-jaxb-with-retrofit-instead-of-simplexml
• http://blog.bdoughan.com/2011/06/jaxb-and-complex-types-with-simple.html
• https://github.com/square/retrofit/blob/master/retrofit-converters/jaxb/src/test/java/retrofit2/converter/jaxb/JaxbConverterFactoryTest.java

[swankjesse]

Try editing JaxbConverterFactoryTest.java, setting it's model type to your model type and it's XML to your XML? If that fails set some breakpoints?

[black-snow]

Replaced the test's XML with

static final String SAMPLE_CONTACT_XML = "<?xml version=\"1.0\" encoding=\"utf-8\"?> <feed xmlns=\"http://www.w3.org/2005/Atom\" xmlns:idx=\"urn:atom-extension:indexing\"> <id>tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc</id> </feed> ";
static final Feed SAMPLE_CONTACT = new Feed("tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc");

Replace Contact with Feed:

package retrofit2.converter.jaxb;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "feed")
final class Feed {
  @XmlElement(required = true)
  public final String id;

  @SuppressWarnings("unused") // Used by JAXB.
  private Feed() {
    this("");
  }

  public Feed(String id) {
    this.id = id;
  }

  @Override public boolean equals(Object o) {
    return o instanceof Feed
        && ((Feed) o).id.equals(id);
  }

  @Override public int hashCode() {
    return Arrays.asList(id).hashCode();
  }
}

Changed occurrences of Contact with Feed, name with id and Jenny with tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc in JaxbConverterFactoryTest.java.

Results:

Test set: retrofit2.converter.jaxb.JaxbConverterFactoryTest
-------------------------------------------------------------------------------
Tests run: 6, Failures: 3, Errors: 0, Skipped: 0, Time elapsed: 0.695 sec <<< FAILURE!
userSuppliedJaxbContext(retrofit2.converter.jaxb.JaxbConverterFactoryTest)  Time elapsed: 0.052 sec  <<< FAILURE!
org.junit.ComparisonFailure: expected:<...<?xml version="1.0" [encoding="utf-8"?> <feed xmlns="http://www.w3.org/2005/Atom" xmlns:idx="urn:atom-extension:indexing"> <id>tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc</id> </feed> ]"> but was:<...<?xml version="1.0" [?><feed><id>tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc</id></feed>]">
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at retrofit2.converter.jaxb.JaxbConverterFactoryTest.userSuppliedJaxbContext(JaxbConverterFactoryTest.java:107)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    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.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    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$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
    at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
    at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)

xmlResponseBody(retrofit2.converter.jaxb.JaxbConverterFactoryTest)  Time elapsed: 0.019 sec  <<< FAILURE!
org.junit.ComparisonFailure: expected:<...converter.jaxb.Feed@[bc1e4518]> but was:<...converter.jaxb.Feed@[1f]>
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at retrofit2.converter.jaxb.JaxbConverterFactoryTest.xmlResponseBody(JaxbConverterFactoryTest.java:88)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    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.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    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$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
    at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
    at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)

xmlRequestBody(retrofit2.converter.jaxb.JaxbConverterFactoryTest)  Time elapsed: 0.012 sec  <<< FAILURE!
org.junit.ComparisonFailure: expected:<...<?xml version="1.0" [encoding="utf-8"?> <feed xmlns="http://www.w3.org/2005/Atom" xmlns:idx="urn:atom-extension:indexing"> <id>tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc</id> </feed> ]"> but was:<...<?xml version="1.0" [?><feed><id>tag:google.com,2005:reader/user/abc/state/com.google/alerts/abc</id></feed>]">
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at retrofit2.converter.jaxb.JaxbConverterFactoryTest.xmlRequestBody(JaxbConverterFactoryTest.java:79)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    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.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    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$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
    at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
    at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)

[black-snow]

What I can see is that the tags' attributes are missing.

[JakeWharton]

Are you saying that this is a bug in Retrofit's converter? Does it work when using JAXB directly with Strings without Retrofit?

[black-snow]

@JakeWharton I don't know whether it's a bug or not. Maybe I'm just stupid.

I now did:

Feed f = JAXB.unmarshal(new StringReader(SAMPLE_CONTACT_XML), Feed.class);
System.out.println("XXX");
System.out.println(f.id);
System.out.println("XXX");
assertThat(f).isEqualTo(SAMPLE_CONTACT);

and it fails, f.id is empty:

Running retrofit2.converter.jaxb.JaxbConverterFactoryTest
XXX

XXX

[black-snow]

After removing xmlns="http://www.w3.org/2005/Atom" xmlns:idx="urn:atom-extension:indexing" from the feed tag it works.
Seems to be a namespace issue.

[black-snow]

Thought I'd extend the JAXBConverterFactory but JaxbRequestConverter can't be extended :/
And JaxbConverterFactory is final 😃 🔫

[black-snow]

Ain't seem to be an issue with retrofit but with JAXB.

Couldn't manage to get it working with (empty) namespace so I'll filter the namespace from the responses:

OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
clientBuilder.
        addInterceptor(new Interceptor() {
            @Override
            public Response intercept(Chain chain) throws IOException {
                Request request = chain.request();
                Response response = chain.proceed(request);
                ResponseBody body = response.body();
                // filter response here
                ResponseBody newBody = ResponseBody.create(MediaType.parse("application/xml"), "<?xml version=\"1.0\" encoding=\"utf-8\"?> <feed> <id>xyz</id> </feed>");
                response = (new Response.Builder())
                    .body(newBody)
                    .code(response.code())
                    .headers(response.headers())
                    .message(response.message())
                    .protocol(response.protocol())
                    .receivedResponseAtMillis(response.receivedResponseAtMillis())
                    .request(response.request())
                    .build();
                return response;
            }
        });