This is how I do it. Create a script I call it findclass in some location on the path. /usr/local/bin is a good place, I prefer $HOME/bin. Remember to chmod this script to 755.

#!/bin/bash
find -iname "*.jar" | xargs -i unzip -l {} | less

In case you are new to less, here’s how you navigate:
1. To find a particular class say com.xyz.abc.MyClass, you type: 

/com.xyz.abc.MyClass

2. To find what jar contains this class, you type: 

?Archive: