Migrating to GlassFish
By satishkumar on May 18, 2006
If you are thinking of moving your existing enterprise application over to GlassFish, the first Java EE 5 compliant application server, but worried about migration woes, don't fret! There is help on hand by way of Sun's Application Server Migration Tool. This tool allows you to migrate your existing enterprise applications archives (ear's), web archives (war's), resource archives (rar's) and source code from a host of supported application server's over to GlassFish. And, the tool is free to use!
So, what does the tool do?
The tool works on the input archive or source code to translate the runtime deployment descriptors from the source application server format to GlassFish complaint ones. It also parses the JSP and Java source code files (in case of source code input) and provides runtime support for certain custom JSP tags and proprietary API's. It generates ANT based scripts to build the archive in case of source code inputs. In case of archive inputs, it rebundles the migrated archive.
The migration tool can help you migrate to GlassFish from earlier versions of Sun's Application Server and a host of other competitive application servers such as BEA Weblogic - 5.x, 6.x, 8.x, WebSphere – 4.x, 5.x, Jboss 3.x and Apache Tomcat.
How to use the tool?
The tool is available for download as a zip archive. It needs to be downloaded and extracted to a location on your local harddisk. You will need to make sure you have JDK 5 and GlassFish installed on the machine and you should have the JDK_PATH, J2EE_PATH, AS_HOME and ASMT_HOME environmental variables setup correctly. The complete set of installation instructions are available here. The tool can be run in either the UI mode or the command line mode. All you need to do is specify the location of your archive/ source code, the app server for which the source was created, point it to where you want the output to be generated and you are all set. Once the migration is complete, the tool generates a comprehensive report describing what has been migrated, what else needs to be done and errors, if any.
What the tool can't do?
The tool provides limited support for proprietary API's and custom JSP tags. The rest of the unsupported API usages show up in the report and need to be manually corrected before you can deploy your application. Hence, before you start the migration, it would be a good idea to run the Application Verification Kit (AVK) to get an idea of how Java EE compliant your application is. The report from AVK should be able to give you a fairly good idea of how much effort is involved in the migration.
If you need more help with this tool, you can refer to the online documentation.