Some exceptions we will get and how to resolve when we upgrade the application from java 1.4 to 1.6

This file will be keep on updating.

1.java.lang.IllegalAccessError: class javax.activation.SecuritySupport12 cannot access its superclass javax.activation.SecuritySupport

This issue will happen when we are using the old activation.jar with mail.jar. solution is delete the activation.jar. Sometimes if we are using weblogic.jar, there is a subdirectory javax.activation also need to be deleted.