Chapter 6: Switch to Another JRE

Note  Microsoft does not guarantee or warrant that alternate JREs will work correctly in your environment. Test all JREs sufficiently during implementation to ensure that all of your needs are met.

Several vendors have announced that they will ship an alternate Java runtime environment (JRE) on their computers when Microsoft is no longer able to support the MSJVM. Whether you adopt this solution depends upon your business needs, including portability, performance, reliability, versions, and maintenance.

Although vendors represent that their JREs comply with relevant Java specifications, all JREs are not necessarily equivalent for your needs. Not all implementations of Java specifications are identical, and you should ensure that you test any alternate JRE prior to pursuing this option.

Current Visual J++ code may need to be ported to work with an alternate JRE. The use of Microsoft extensions is easy to find in current J++ source files; you can find Java source files that make use of the @com directive by using a CMD.EXE command of the form:

    find /I "@com" c:\src\*.*

Similar commands will find other extensions, such as the @dll and @security directives. Once you have identified the use of the extensions, you can gauge the effects of removing them.

The use or removal of the Microsoft extensions makes no syntactic difference to the Java code because the directives are embedded in comments. It is possible to turn the extensions off with options to the javac command, so you can easily compare the effect of running the application with and without the extensions.

Alternate JREs are deployed throughout your organization using the same means by which you normally install new applications on user machines. For more information on properly installing an alternate JRE please refer to vendor documentation. If you choose to install an alternate JRE, any problems you experience with Java support will not be addressed by Microsoft, and are subject to relevant support and license agreements with the appropriate vendor of the alternate JRE.

The following is a partial list of available alternate JREs and is not intended to represent all available alternate JREs:

Sun JRE for Windows: 

IBM JRE (as part of the IBM WebSphere SDK for Web Services):

BEA JRockit:



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