Access to java jar files

The following line fails

pagenum = Integer.parseInt(pagenum).toString();

with

The error message was: class bsh.EvalError (line 5): Integer .parseInt ( pagenum ) -- Error in method invocation: Static method parseInt( java.lang.Integer ) not found in class'java.lang.Integer'

I thought the standard java classes were available without me doing anything. Or do I need to copy the jar file to a particluar location and/or include an Import statement