I will explain Interaction between BPEL 2 BPEL Process with simple example.
Complete Process -
BPEL Process 1 will call BPEL Process 2.Both are Synchronous processess.
http://eoracleapps.blogspot.com/2009/11/how-to-call-synchronous-bpel-process.html for More Information on "OrderInfo" Message Type.
Import theMessage type in your Project and assign that to input and output variable of BPEL Process 1.
BPEL Process -1
Design BPEL Process 1 with simple Assign activity b/w input and output variables.
Open the BPEL Process 1 again and add INVOKE actvity in flow to call the BPEL process 2(BPELProcess3).
Configure the Invoke activity as shown below.
In Assign_1 activity in Process 1 , assign the input variable to input of the invoke activity as shown below.
Add another Assign activity in Process 1 , right below the invoke actity and assign the outcome of the invoke activity to output of BPEL Process.
Compile your Project and Deploy.
Testing - Run the BPEL Process and add the Input data ( Based on Order Info Element).
Verify the output.