Mac has no Java 6. The Java 6 beta that Apple released is only 64-bit, which is no good for running Eclipse. Not only is this a major annoyance, it is a problem for developers that need to profile and take heap dumps of their applications.

Some time ago I found this post by Landon Fuller which supposedly launches Eclipse on SoyLatte. While I believe that Landon is a genius, it did not work for me. Well lately I've needed to take some heap dumps, so I tried again.

Here's what worked for me:

/Users/dgreen/Documents/java/soylatte16-i386-1.0.2/bin/java -server -Xms128m -Xmx1536m -XX:MaxPermSize=256m -Dosgi.requiredJavaVersion=1.5 -Dorg.eclipse.swt.internal.carbon.smallFonts -Djava.library.path=/Users/dgreen/bin/jnilib -cp /Applications/eclipse/ org.eclipse.equinox.launcher.Main -os macosx -ws carbon -arch x86 -showsplash -launcher /Applications/eclipse/ -name Eclipse --launcher.library /Applications/eclipse/ -startup /Applications/eclipse/ -data /Users/dgreen/Documents/workspace -launcher /Applications/eclipse/ -keyring /Users/dgreen/.eclipse_keyring -consoleLog -showlocation -vm /Users/dgreen/Documents/java/soylatte16-i386-1.0.2

I also had to extract all *.jnilib files from eclipse/plugins/org.eclipse.swt.carbon.macosx_3.4*.jar and copy them into /Users/dgreen/bin/jnilib
Finally, Eclipse running in a Java 6 VM on a Mac! Apple, time to get your Java act in gear.

Update 2008-08-21: SoyLatte 1.0.2 works for me, but 1.0.3 and OpenJDK 7 darwin packages posted here don't. If you find a solution, please let me know!

Update 2009-05-11: See this related article Eclipse 3.5 (Galileo) on Java 7