Porting from MRJ/MRJVM to standard JVM

[Addle Jones]

I have the source code for an application that was written using
Microsoft's apparently defunct variant of Java. It does not compile
under the standard JDK from Sun and I get a lot of errors that
are unfamiliar to me. I need to update this application so that it
runs under a standard JVM.

I don't know a thing about Microsoft's variant of Java. Is there
some place I can get a quick summary of the differences, just
enough to help me rip out the code that depends on Microsoft's
version?

 

[Thomas Hawtin]

I have the source code for an application that was written using
Microsoft's apparently defunct variant of Java. It does not compile
under the standard JDK from Sun and I get a lot of errors that
are unfamiliar to me. I need to update this application so that it
runs under a standard JVM.

I don't know a thing about Microsoft's variant of Java. Is there
some place I can get a quick summary of the differences, just
enough to help me rip out the code that depends on Microsoft's
version?

In terms of language, the main Microsoft specific feature is delegates.
Declarations with the 'delegate' keyword will need to be replaced by
interfaces. Where methods are treated as if they are fields, an inner
class will easily replace it.

More of a problem is the use of Microsoft specific libraries (which IIRC
have package names starting with com.ms, that indicates they are from
Morgan Stanley...).

Tom Hawtin

 

[Steve W. Jackson]

I have the source code for an application that was written using
Microsoft's apparently defunct variant of Java. It does not compile
under the standard JDK from Sun and I get a lot of errors that
are unfamiliar to me. I need to update this application so that it
runs under a standard JVM.

I don't know a thing about Microsoft's variant of Java. Is there
some place I can get a quick summary of the differences, just
enough to help me rip out the code that depends on Microsoft's
version?

MRJ is the Macintosh Runtime for Java and has nothing to do with
Microsoft. It too is defunct.

 

[Addle Jones]

MRJ is the Macintosh Runtime for Java and has nothing to do with
Microsoft. It too is defunct.

The code I have used to run on both Windows and (classic) Mac,
so maybe mrj is not the right term. At the time this code was
written, I thought Apple had some kind of deal going with Microsoft
to support their Java extensions. Maybe I don't have it right. Or
maybe the code was written with J++. Unfortunately, the people who
originally wrote the code are gone and completely out of
contact.

In any case, it seems that Apple now has a standard JVM in OS X. I
need the code to run on current Mac OS X and Windows systems, and
would not mind if it ran on other systems as well.

 

[Steve W. Jackson]

The code I have used to run on both Windows and (classic) Mac,
so maybe mrj is not the right term. At the time this code was
written, I thought Apple had some kind of deal going with Microsoft
to support their Java extensions. Maybe I don't have it right. Or
maybe the code was written with J++. Unfortunately, the people who
originally wrote the code are gone and completely out of
contact.

In any case, it seems that Apple now has a standard JVM in OS X. I
need the code to run on current Mac OS X and Windows systems, and
would not mind if it ran on other systems as well.

Then you're in luck...

Apple currently has JDK 1.6 in development with no official word on its
scheduled release. But all Mac OS X releases have included a JDK. The
current version, Mac OS X 10.4 (aka Tiger), came (if memory serves) with
1.4 that was updated to 1.4.2 and later 1.5 became available...I may be
remembering that incorrectly. But which specific Java you want may
depend in some part on whether you have a requirement to support
specific versions of Mac OS X.

I suggest visiting <http://developer.apple.com/java/> for a start.
While Apple's JVM does in fact support Swing and all the usual stuff,
its UI and environment will need some extra steps if you want your
application to be able to act like a traditional Mac application -- one
that can be double-clicked, put a proper icon on the Dock, have a proper
name in the menu bar, etc. But pure, unadulterated Swing will work and
simply not look quite like the norm. You can find a wealth of
information starting there. If you want more, you might want to
subscribe to the java-dev mailing list that's offered. It's not too
high-traffic (though it has its days) and its archive is available to
search. You'll find a link on that page for more on it.

= Steve =

 

[=?ISO-8859-1?Q?Arne_Vajh=F8j?=]

I have the source code for an application that was written using
Microsoft's apparently defunct variant of Java. It does not compile
under the standard JDK from Sun and I get a lot of errors that
are unfamiliar to me. I need to update this application so that it
runs under a standard JVM.

I don't know a thing about Microsoft's variant of Java. Is there
some place I can get a quick summary of the differences, just
enough to help me rip out the code that depends on Microsoft's
version?

If you posted some of the errors, then you may get
some more specific advice.

Arne