Hibernate exception _$$_javassist_0 cannot be cast to javassist.util.proxy.Proxy

Question

Hello I am using developnig java web application and I am getting the next exception when I am trying to fetch data using hibernate

java.lang.ClassCastExcept         


        

Answer 1

In my case problem was that there were two javassist libraries in classpath. One from org.hibernate and other from org.apache.struts.xwork. Solved by removing latter.

Answer 2

Check your return type T or List<T>of results

Answer 3

Resolved issue for weblogic based spring-hibernate-jpa application. The class cast exception occurs because of conflicting jars of web logic server and javassist jar. Add the javassist-3.18.0-ga.jar or higher version into your class path and then add below lines of code into your weblogic-application.xml file and it should resolve your issue.

<wls:prefer-application-packages>
        <wls:package-name>javassist.*</wls:package-name>
  </wls:prefer-application-packages>

Answer 4

I had the same issue when using hibernate + titles. Solved by excluding javassist from tiles-extras:

<dependency>
  <groupId>org.apache.tiles</groupId>
  <artifactId>tiles-extras</artifactId>
  <version>3.0.5</version>
  <exclusions>
    <exclusion>
      <groupId>jboss</groupId>
      <artifactId>javassist</artifactId>
    </exclusion>
  </exclusions>
</dependency>

Answer 5

If you are deploying your hibernate based application on the weblogic server or similar, you are going to have an earlier version of javassist jar available inside the modules folder of the server. This would cause the conflict talked about in the earlier answers where you may end up in having more than one jars in the classpath.

specifically for weblogic add following in your weblogic-application.xml

add package-name javaassist.* to ensure that latest is picked up.

<?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-application
   xmlns:wls="http://www.bea.com/ns/weblogic/weblogic-application"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/javaee_5.xsd http://www.bea.com/ns/weblogic/weblogic-application http://www.bea.com/ns/weblogic/weblogic-application/1.0/weblogic-application.xsd">

   <wls:ejb>
      <wls:start-mdbs-with-application>false
      </wls:start-mdbs-with-application>
   </wls:ejb>

   <wls:prefer-application-packages>
      <wls:package-name>antlr.*</wls:package-name>
      <wls:package-name>org.apache.commons.*</wls:package-name>
      <wls:package-name>org.apache.xmlbeans.*</wls:package-name>
      <wls:package-name>org.springframework.*</wls:package-name>
      <wls:package-name>org.hibernate.*</wls:package-name>
      <wls:package-name>org.joda.*</wls:package-name>
      <wls:package-name>javax.persistence.*</wls:package-name>
      <wls:package-name>com.google.*</wls:package-name>
      <wls:package-name>com.ibm.icu.*</wls:package-name>
      <wls:package-name>org.apache.axiom.*</wls:package-name>
      <wls:package-name>javassist.*</wls:package-name>
   </wls:prefer-application-packages>
</wls:weblogic-application>

Answer 6

Like anquegi has already commented. You have a lib conflict. Back hibernate to 4.2.7.Final will not solve your lib conflict. Run mvn dependency:tree -Dverbose and look to javassist different versions. In my case, I need to exclude javassist from Hibernate dependencies.

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>${hibernate.version}</version>
    <exclusions>
        <exclusion>
            <groupId>org.javassist</groupId>
            <artifactId>javassist</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>${hibernate.version}</version>
    <exclusions>
        <exclusion>
            <groupId>org.javassist</groupId>
            <artifactId>javassist</artifactId>
        </exclusion>
    </exclusions>
</dependency>

This may help others in to future.