Illegal to inject a message body into a singleton into public org.codehaus.jackson.jaxrs.JacksonJsonProvider
Published: July 12, 2011 , Updated: July 12, 2011 , Author: mkyong
Problem
Using Jackson as JSON provider in RESTEasy.
<dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxrs</artifactId> <version>2.2.1.GA</version> </dependency> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jackson-provider</artifactId> <version>2.2.1.GA</version> </dependency>
With RESTEasy auto scanning enabled.
<context-param> <param-name>resteasy.scan</param-name> <param-value>true</param-value> </context-param>
When starting up, it hits following errors and failed to start up any of the RESTEasy services.
SEVERE: Exception sending context initialized event to listener instance of class org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap java.lang.RuntimeException: Unable to instantiate MessageBodyReader at org.jboss.resteasy.spi.ResteasyDeployment.registerProvider(ResteasyDeployment.java:505) at org.jboss.resteasy.spi.ResteasyDeployment.registration(ResteasyDeployment.java:305) at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:225) //... Caused by: java.lang.RuntimeException: Illegal to inject a message body into a singleton into public org.codehaus.jackson.jaxrs.JacksonJsonProvider( org.codehaus.jackson.map.ObjectMapper,org.codehaus.jackson.jaxrs.Annotations[]) ... 20 more
Solution
There is problem to integrate RESTEasy with Jackson if “auto scanning” mode is enabled. Hope it will fixed in later released.
To fix it, disabled the auto scanning feature, and register your RESTEasy service manually in web.xml.
<!-- disabled auto scanning <context-param> <param-name>resteasy.scan</param-name> <param-value>true</param-value> </context-param> --> <context-param> <param-name>resteasy.resources</param-name> <param-value>com.mkyong.JacksonRestServiceHere</param-value> </context-param>
[...] the RESTEasy auto scanning, and register your REST service manually, otherwise, you will hits this error. Hope it get fix in future release.File : web.xml <!– disabled auto scan <context-param> [...]