Java SecurityException: signer information does not match

Question

I recompiled my classes as usual, and suddenly got the following error message. Why? How can I fix it?

java.lang.SecurityException: class \"Chinese_English_D         


        

Answer 1

A. If you use maven, an useful way to debug clashing jars is:

mvn dependency:tree

For example, for an exception:

java.lang.SecurityException: class "javax.servlet.HttpConstraintElement"'s signer information does not match signer information of other classes in the same package

we do:

mvn dependency:tree|grep servlet

Its output:

[INFO] +- javax.servlet:servlet-api:jar:2.5:compile
[INFO] +- javax.servlet:jstl:jar:1.2:compile
[INFO] |  +- org.eclipse.jetty.orbit:javax.servlet.jsp:jar:2.2.0.v201112011158:compile
[INFO] |  +- org.eclipse.jetty.orbit:javax.servlet.jsp.jstl:jar:1.2.0.v201105211821:compile
[INFO] |  +- org.eclipse.jetty.orbit:javax.servlet:jar:3.0.0.v201112011016:compile
[INFO] +- org.eclipse.jetty:jetty-servlet:jar:9.0.0.RC2:compile

shows clashing servlet-api 2.5 and javax.servlet 3.0.0.x.

B. Other useful hints (how to debug the security exception and how to exclude maven deps) are at the question at Signer information does not match.