William van den Heuvel William van den Heuvel
Freelance software developer


Since 2001 I have experience with Java. I turned my focus on distributed client/server systems involving Java clients connecting to the IBM mainframe server. I have practical experience designing and developing Web applications using Enterprise Java (JSP, Servlet, EJB) and TCP gateways on the IBM mainframe. Following is a brief resume of my experience with Java.

The resume is in reverse chronological order.

2002-2004 My last big project on the IBM mainframe (2002) was a connector that involved writing a Java EJB on the client side, and a concurrent TCP server on the mainframe side. The communication was done using native TCP/IP sockets and the request/response messages were wrapped in XML. I wrote the XML parser/generator on the IBM mainframe and used an existing XML parser in the EJB. This project also involved writing Servlets, and the HTML and Javascript on the web browser.
Winterthur Versicherungen
In 2001, I started taking interest in client/Server systems. I had written a stand-alone Java application using the Swing GUI and TCP/IP sockets to communicate with a TCP server on the mainframe. This was a RACF security program that enabled users to update their password on the IBM mainframe without requiring a TSO emulator on the PC.
(Munich, D)
In 2001, I had an assignment at the HypoVereinsbank in Munich to investigate the feasibility of using Java on the z/OS platform. This included developing a pilot application that involved language communication between Java and the other programming languages that were in common use on the mainframe (primarily C, Cobol and PL/1). This communication was accomplished using the Java Native Interface (JNI) and z/OS Language Environment (LE).