10.6: Re-enable Java 1.4.2 and Java 1.5 apps in Snow Leopard

Many applications that relied on Java 1.4.2 and Java 1.5 stopped working in Snow Leopard, because Apple removed these Java versions from the system. Upgrading to the lastest versions of many applications usually will solve the problem. However, your favorite application may not have a Snow Leopard compatible upgrade. For these applications, re-installing Java 1.4.2 and/or Java 1.5 is necessary. Sometimes, even this is not enough. As an example, Apple also removed the Cocoa-Java bridge from Snow Leopard, which some Java applications such as PDFLab depended on. Reinstalling the Cocoa-Java bridge along with the proper version of Java is necessary to re-enable these applications on Snow Leopard. For example, getting PDFLab working again in Snow Leopard requires reinstalling Java 1.4.2 and the Cocoa-Java bridge. Read on for a how-to...

Installing Java 1.4.2 and/or Java 1.5 on snow Leopard: 

The following is based on two blog posts: Using Java 1.5 and Java 1.4 on Snow Leopard and Installing Java 1.5 on Snow Leopard:

1. Download the official Java package from Apple: Java for Mac OS X 10.5 Update 4, dated June 15, 2009.
2. Use the excellent shareware utility Pacifist to open the downloaded JavaForMacOSX10.5Update4.pkg file.
3. First use Finder to go to System » Library » Frameworks » JavaVM.framework » Versions and delete the two aliases (symlinks) 1.5 and 1.5.0. Don’t skip this step, because otherwise the extraction will follow the symlinks and overwrite the contents of the 1.6.0 folder, oops!
4. In Pacifist, drill down into Contents » System » Library » Frameworks » JavaVM.framework » Versions.
5. In Pacifist, select 1.5 and 1.5.0, Control-click on the selection, and chose Install to Default Location from the pop-up menu.
6. In the instructions above, the same applies for version 1.4.2.

Installing the Cocoa-Java Bridge: 

This is based on Getting back the Cocoa-Java bridge in Snow Leopard: 

Copy from a working Leopard (10.5) installation the following folders:

1. the com directory in /System/Library/Java
2. the eight files ending with .dylib in /usr/lib/java (four of these are regular files, the other four are symlinks; if you prefer, you can copy just the files and recreate the symlinks by hand).