Spring JSON request getting 406 (not Acceptable)

406 Not Acceptable

The resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headers sent in the request.

So, your request accept header is application/json and your controller is not able to return that. This happens when the correct HTTPMessageConverter can not be found to satisfy the @ResponseBody annotated return value. HTTPMessageConverter are automatically registered when you use the <mvc:annotation-driven>, given certain 3-d party libraries in the classpath.

Either you don't have the correct Jackson library in your classpath, or you haven't used the<mvc:annotation-driven> directive.

I successfully replicated your scenario and it worked fine using these two libraries and no headers="Accept=*/*" directive.

• jackson-core-asl-1.7.4.jar
• jackson-mapper-asl-1.7.4.jar

I had same issue, with Latest Spring 4.1.1 onwards you need to add following jars to pom.xml.

<dependency>    <groupId>com.fasterxml.jackson.core</groupId>    <artifactId>jackson-core</artifactId>    <version>2.4.1</version></dependency><dependency>    <groupId>com.fasterxml.jackson.core</groupId>    <artifactId>jackson-databind</artifactId>    <version>2.4.1.1</version></dependency>

also make sure you have following jar:

<dependency>    <groupId>org.codehaus.jackson</groupId>    <artifactId>jackson-core-asl</artifactId>    <version>1.9.13</version></dependency><dependency>    <groupId>org.codehaus.jackson</groupId>    <artifactId>jackson-mapper-asl</artifactId>    <version>1.9.13</version></dependency>

406 Spring MVC Json, not acceptable according to the request "accept" headers

There is another case where this status will be returned: if the Jackson mapper cannot figure out how to serialize your bean. For example, if you have two accessor methods for the same boolean property, isFoo() and getFoo().

What's happening is that Spring's MappingJackson2HttpMessageConverter calls Jackson's StdSerializerProvider to see if it can convert your object. At the bottom of the call chain, StdSerializerProvider._createAndCacheUntypedSerializer throws a JsonMappingException with an informative message. However, this exception is swallowed by StdSerializerProvider._createAndCacheUntypedSerializer, which tells Spring that it can't convert the object. Having run out of converters, Spring reports that it's not being given an Accept header that it can use, which of course is bogus when you're giving it */*.

There is a bug for this behavior, but it was closed as "cannot reproduce": the method that's being called doesn't declare that it can throw, so swallowing exceptions is apparently an appropriate solution (yes, that was sarcasm). Unfortunately, Jackson doesn't have any logging ... and there are a lot of comments in the codebase wishing it did, so I suspect this isn't the only hidden gotcha.