Maltab 2013b Java classloader error

I wrote a matlab script that is calling java classes, created a javaclasspath.txt and added paths to dependency jar files, which is then loaded statically when Matlab starts. When testing in 2014b version, code runs without any errors. However, when the same code is run in 2013b version, I run into following error:

Undefined variable "edu" or class "edu.example.ExampleClass".

How can I print more detailed error message to find out if this is a class loader issue? Is there a Matlab log file that will show class loader failures? Code should work in 2013b version as a requirement.