org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15 – Tomcat 7, JDK incompatibilty? [duplicate]
I was seeing this error with Tomcat 7.0.26. To answer your question, Tomcat is to blame: https://issues.apache.org/bugzilla/show_bug.cgi?id=53735 Upgrading to version 7.0.53 fixed it for me (according to the linked issue, the fix should be in 7.0.30 and later).