I am trying to dynamically create a new class in Spark using javaassist API. The code seems very simple just invoking makeClass API on a hardcoded class name. The code works find outside Spark environment but getting this chedkNotFrozen exception when I am running the code inside Spark Code Excerpt: ClassPool pool = ClassPool.getDefault() CtClass regExClass= pool.makeClass("TestClass14",baseFeatureProcessor) Exception Details: ###################### Exception make Class java.lang.RuntimeException: TestClass14: frozen class (cannot edit) at javassist.ClassPool.checkNotFrozen(ClassPool.java:617) at javassist.ClassPool.makeClass(ClassPool.java:859)