Exception "Duplicate field name&signature in class file" should report the name and signature of the field

Sometimes I get the following exception when running unit tests:

java.lang.ClassFormatError: Duplicate field name&signature in class file CampaignClient
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

Unfortunately, without a field name + signature I have no way of knowing what
is triggering the problem. The class in question is quite big so removing
code by trial and error is very time consuming.

Would like:

java.lang.ClassFormatError: Duplicate field name LOG with signature
org.slf4j.Logger in class file CampaignClient