How to handle custom developments in customer name space during a Java Upgrade.
You want to upgrade a NW portal from 7.0X to NW 7.30 or NW 7.4. I would explain in this document a procedure for carrying forward the custom developments in customer name space or components other than name space "sap.com" into the target release .
All SAP standard delivered objects are in name space "sap.com". Using NWDI the customer develop his custom applications in his own name space . During the BUILD_COMPONENT_LIST phase of the upgrade ,the upgrade tool displays a list of all the SAP and custom objects which are not a part of the stackXML . We need to take a decision on these objects. The upgrade offers two options as "SCAN INBOX" or "REMOVE" . Now if you want to proceed with keeping the components , you have to provide a successor to these packages in the EPS in box . If no successor is provided the components will be completely removed.
What can be done to keep the custom developments
Now on releases 7.0x the used java version id java 1.4.1 or 1.5.1 depending upon the release. On Nw 7.3 or higher the java gets switched to SAPJVM 6.x.
The custom objects are on NW 7.0 release . Now these successor packages are based on NWDI on NW7.3 based on SAPJVM 6.X . So the successor packages are SCA files created on target release . Now how to migrate the packages from NW 7.0x to NW 7.3 and higher is clearly described in the below SCN doc
Now the components deployed in NW 7.3 NWDI have to be bundled into SCA file and they have to be provided as successor package . The SUM tool only accepts SCA files. If now successors are provided , the components will be un-deployed as the system is being upgraded to NW 7.3 or higher up releases.
Now there is another crude way of carrying forward the changes. You may have to take a backup of the existing objects in lower release. During the BUILD_COMPONENT_LIST phase ,you may choose the option to "Remove" . The upgrade tool will upgrade the system and you may redeploy the custom developments again. But this approach will pollute the system with SDA's which are not bundled into SCA's . This will again cause problem during the next upgrade if components are not present as SCA's . So this is not recommended as a correct approach.