Sooooo, for whatever reason you and your companys applications are taking the leap. Someone in some meeting somewhere decided that it would be a good idea for some reason for you and/or your company to be using the SAP Web AS 6.40. So, now, guess what? Here it comes like it or not upgrade.
Youve been through upgrades before over the years. But, once again, this one has a different flavor. This time theres this J2EE engine that needs to be upgraded, too. Your company has even deployed java applications on the 6.20 J2EE engine. Now that your company has decided to upgrade, you have to find out what needs to be done to upgrade from Web AS 6.20 to Web AS 6.40.
First, I am ignoring the scenario for upgrading from Web AS 6.10 to 6.40. The reason is, the focus of this blog is what needs to be done for the J2EE engine and applications. With 6.10, there was no J2EE engine, so there is no J2EE to upgrade
There are two aspects that need to be considered during the upgrade; what needs to be done for the system and what needs to be done for the applications. First, a couple of things to know about the ABAP part of the upgrade. If you have done an upgrade to a Web AS 6.x based system before, there is nothing new here. Aside from performance tweaks, the overall technology the system switch upgrade is the same. ABAP applications migrate over to the new release the same way as before, during the upgrade of the repository. Also, while a Web AS ABAP-only installation can be converted to a ABAP+Java installation by simply installing the J2EE engine, it is not possible to add-in an ABAP system to an existing standalone Java-only installation. Web AS Java-only installations can only be upgraded to Java-only installations.
Unfortunately, the Java part of the upgrade isnt as mature as the ABAP part yet (but, this too I expect to change in future upgrades, due to the addition of the database). In fact, upgrade really isnt the correct term for what needs to be done to upgrade the J2EE engine. The 6.40 J2EE Engine is implemented with a completely new architecture new cluster communication, new service framework, new features. Therefore, it is not possible to upgrade a J2EE Engine 6.20 to 6.40 directly. From the system standpoint, you must uninstall the 6.20 J2EE engine and then install a new 6.40 J2EE Engine. From the application standpoint you must redeploy all applications that were running on the 6.20 J2EE Engine.
For an application to successfully deploy on the 6.40 engine, the applications EAR file must contain:
- All the application components
- application.xml, which must be J2EE 1.2 or 1.3 compliant
- application-j2ee-engine.xml a SAP J2EE Engine-specific deployment descriptor, which contains the references to external libraries and services, specifies the application failover, and so on.
The applications running on J2EEEngine 6.20 are J2EE 1.2 compatible. If they have some additional deployment properties, these properties are specified in the standard application.xml. These applications do not have application-j2ee-engine.xml.
You may say well, thanks, now, for piquing my interest. But are you going to tell me exactly how to port the application, the differences in the architecture that affect my application, the incompatibles between 6.20 and 6.40 and so on? Well, actually, no, I am not. That would make this blog much too long and detailed. Fortunately, there is a Migration Manual to help you with all of this. It describes all the nitty-gritty detail that the java developers (along with help from the systems folks) need to know to get their 6.20 J2EE application up and running on the 6.40 J2EE engine.