How to connect Java (Portal) with Abap

Hi Experts,

We have a requirement to connect new build Portal server with old ABAP Server as Backend. Both Servers Host names and IP Addresses are different. Can you Please provide me following answers

1. How to connect both Servers

2. We want to get the data from Abap and want to use in Poral ie Abap will be backend. How to do that

3. What are the Post configurations need to be done

Awaiting for your Reply's. This is little bit urgent.

Thanks & Regards

Santosh K