title: java.lang.IncompatibleClassChangeError
body: <p>I'm trying to a JPA annotation one -to- one. but getting following error</p>
  
  <pre><code>Exception in thread "main" java.lang.IncompatibleClassChangeError: class org.hibernate.cfg.ExtendedMappings has interface org.hibernate.cfg.Mappings as super class
  at java.lang.ClassLoader.defineClass1(Native Method)
  at java.lang.ClassLoader.defineClassCond(Unknown Source)
  at java.lang.ClassLoader.defineClass(Unknown Source)
  at java.security.SecureClassLoader.defineClass(Unknown Source)
  at java.net.URLClassLoader.defineClass(Unknown Source)
  at java.net.URLClassLoader.access$000(Unknown Source)
  at java.net.URLClassLoader$1.run(Unknown Source)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.net.URLClassLoader.findClass(Unknown Source)
  at java.lang.ClassLoader.loadClass(Unknown Source)
  at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
  at java.lang.ClassLoader.loadClass(Unknown Source)
  at org.hibernate.cfg.AnnotationConfiguration.createExtendedMappings(AnnotationConfiguration.java:182)
  at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:272)
  at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1377)
  at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)
  at com.HiberAnnJS.main(HiberAnnJS.java:21)
  </code></pre>
  
  <p>I don't know what i have to do. </p>