Java.Lang.ClassNotFoundException : Javassist.Util.Proxy.MethodFilter

Problem

Using Hibernate 3.6.3, but hits this javassist not found error, see below for error stacks :

Caused by: java.lang.NoClassDefFoundError: javassist/util/proxy/MethodFilter
 ...
 at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:77)
 ... 16 more
Caused by: java.lang.ClassNotFoundException: javassist.util.proxy.MethodFilter
 at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
 at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
 ... 21 more

Solution

javassist.jar is missing,