Recommended solutions based on your search
Two or more classes in the same package with different signature data, especially when they come from different JARs that have signatures signed with different certificates. Make sure all JARs are signed using the same certificate.
Solutions on the web
java.lang.SecurityException: class "oracle.forms.fd.JCalendar"'s signer information does not match signer information of other classes in the same package
at java.lang.ClassLoader.checkCerts(Unknown Source)
at java.lang.ClassLoader.preDefineClass(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)