src/main/java/ognl/enhance/ExpressionCompiler.java
protected ClassPool getClassPool(OgnlContext context, EnhancedClassLoader loader)
    {
        if (_pool != null)
            return _pool;

        _pool = ClassPool.getDefault();
        _pool.insertClassPath(new LoaderClassPath(loader.getParent()));

        return _pool;
    }
protected ClassPool getClassPool(OgnlContext context, EnhancedClassLoader loader)
    {
        if (_pool != null)
            return _pool;

        _pool = ClassPool.getDefault();
        _pool.insertClassPath(new LoaderClassPath(loader.getParent()));

        return _pool;
    }
Gets either a new or existing {@link ClassPool} for use in compiling javassist
classes.  A new class path object is inserted in to the returned {@link ClassPool} using
the passed in <code>loader</code> instance if a new pool needs to be created.

@param context
The current execution context.
@param loader
The {@link ClassLoader} instance to use - as returned by {@link #getClassLoader(ognl.OgnlContext)}.
@return The existing or new {@link ClassPool} instance.