RESTEASY003145: Unable to find a MessageBodyReader of content-type application/json and type class org.keycloak.representations.AccessTokenResponse

Question

I\'m trying to test Keycloak REST API. Instaled the version 2.1.0.Final. I can access the admin through browser with SSL without problems.

I\'m using the code above:

Answer 1

I had the problem, that MatteoM pointed out. I solved with maven-shade-plugin and the transformes tag. Maybe it helps someone.

 <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>3.2.0</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <filters>
                            <filter>
                                <artifact>*:*</artifact>
                                <excludes>
                                    <exclude>META-INF/*.SF</exclude>
                                    <exclude>META-INF/*.DSA</exclude>
                                    <exclude>META-INF/*.RSA</exclude>
                                </excludes>
                            </filter>
                        </filters>
                        <transformers>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <manifestEntries>
                                    <Main-Class>de.example.MainClass</Main-Class>
                                    <X-Compile-Source-JDK>1.8</X-Compile-Source-JDK>
                                    <X-Compile-Target-JDK>1.8</X-Compile-Target-JDK>
                                </manifestEntries>
                            </transformer>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                <resource>META-INF/services/javax.ws.rs.ext.Providers</resource>
                            </transformer>
                        </transformers>
                        <artifactSet/>
                        <outputFile>${project.build.directory}/${project.artifactId}-${project.version}-fat.jar</outputFile>
                    </configuration>
                </execution>
            </executions>
        </plugin>

Answer 2

Or if you create client with proxy then better to initialize provider factory before:

    ResteasyProviderFactory instance=ResteasyProviderFactory.getInstance();
    RegisterBuiltin.register(instance);
    instance.registerProvider(ResteasyJackson2Provider.class);

Answer 3

Adding what Dmitry pointed out here for me causes the following warning:

WARN: RESTEASY002155: Provider class org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider is already registered.  2nd registration is being ignored.

Probably as Bacon said the provider is automatically registered by simply adding the dependency:

    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jackson2-provider</artifactId>
        <version>${resteasy.version}</version>
    </dependency>

Answer 4

I solved !! You must add org.jboss.resteasy.plugins.providers.jackson.ResteasyJacksonProvider into META-INF/services/javax.ws.rs.ext.Providers file then run your executable jar.

Answer 5

On a wildfly 11 / Keycloak context, the following made it work with the RestEasyClientBuilder.

ResteasyClientBuilder builder = new ResteasyClientBuilder();
ResteasyProviderFactory providerFactory = ResteasyProviderFactory.getInstance();
builder.providerFactory(providerFactory);

Double check if ResteasyProviderFactory defaults to true with your Resteasy version. If not, set the builtIns manually:

ResteasyProviderFactory.setRegisterBuiltinByDefault(true);
// or if ResteasyProviderFactory was already instantiated
RegisterBuiltin.register(providerFactory);

Answer 6

I used the dependency to fix this issue

   <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jackson2-provider</artifactId>
        <version>3.1.0.Final</version>
    </dependency>