[Solved] java.lang.IncompatibleClassChangeError: Implementing class

Reason

When you are working with java libraries that internally depend on cglib, then it’s very normal to encounter the below error:

Exception in thread "main" java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
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 java.lang.ClassLoader.loadClassInternal(Unknown Source)
at net.sf.cglib.core.DebuggingClassWriter.toByteArray(DebuggingClassWriter.java:73)
at net.sf.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:26)
at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:216)
at net.sf.cglib.core.KeyFactory$Generator.create(KeyFactory.java:144)
at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:116)
at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:108)
at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:104)
at net.sf.cglib.proxy.Enhancer.(Enhancer.java:69)

This error is due to an incompatible version of cglib with additional jar files in your project, such as asm.

Solution

The solution is very easy. Just place the suitable version of cglib in your classpath.

A correct dependency will look like this:

<dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib</artifactId>
    <version>3.3.0</version>
</dependency>

<dependency>
    <groupId>org.ow2.asm</groupId>
    <artifactId>asm-util</artifactId>
    <version>9.4</version>
</dependency>

Happy Learning !!