Apple has a long history of including Java in its desktop operating systems. The Macintosh Runtime for Java included a JIT compiler developed by Symantec, the standard Java class library from Sun, additional classes providing Macintosh-specific functionality, and the Apple Applet Runner for running Java Applets on the Classic Mac OS without the overhead of a browser.
Macintosh Runtime for Java 1.5 works on computers with 68030, 68040 or PowerPC microprocessors. You also need System 7.5 or later, a minimum of 8 MB of RAM (16 MB is strongly recommended) and at least 7 MB of free disk space. Computers with 68030 or 68040 microprocessors must have 32-bit addressing turned on.
This is what Apple had to say about Java in 1999.
"Our customers want better Java performance in Mac OS and we're committed to giving it to them," said Steve Jobs, Apple's Interim CEO. "We are working hard to make our Java implementation second in speed to none other in th world."
With the JIT compiler Apple expects to significantly boost the performance of Java software running on Mac OS. Industry standard benchmarks on preliminary versions of MRJ combined with the JIT compiler show a 300 percent performance improvement over the current version of MRJ. This is competitive with results seen with Java VMs provided with web browsers for Windows-based computers.
In addition to multiple press releases Apple also started publishing Java development resources on its website, and even went so far as to port a version of QuickTime for Java.
QuickTime for Java brings together Java and QuickTime, allowing developers to create Java software that takes advantage of the power of QuickTime on both Macintosh and Windows. QuickTime for Java harnesses the native power of QuickTime via Java creating an excellent Java multimedia framework.
When the web looked like it would soon be controlled by proprietary frameworks like Java, Steve Jobs didn’t want the Mac to be left out in the cold.
In 2001 during the release of Mac OS X, Apple went as far as to include Java as one of the Mac’s primary Application frameworks right Alongside Classic, Carbon, and Cocoa.
Mac OS X is the only mass-market operating system that comes complete with a fully configured and ready-to-use Java Development Kit. Professional Java developers are increasingly turning to the feature-rich Mac OS X as the operating system of choice for cross-platform Java development projects on the Macintosh and other platforms.
But by 2004 the hype surrounding Java started to settle, and by 2006 is was clear that Java was no longer the pillar of Mac OS X development it had once claimed to be. Java was always a gamble on the Mac. A safe bet for getting the Development Community and Enterprise IT interested in Mac OS X, but a long-shot at making a difference in Mac OS X development. By October 2010 it was clear Objective-C would be the Mac's programing language of choice. With the budding popularity of the iPhone and iPad Apple didn’t need Java anymore to attract attention.
As of the release of Java for OS X v10.6 Update 3, the Java runtime ported by Apple and that ships with OS X is deprecated. Developers should not rely on the Apple-supplied Java runtime being present in future versions of OS X.
Steve Jobs had this to say about Apple's decision to drop Java.
Sun (now Oracle) supplies Java for all other platforms. They have their own release schedules, which are almost always different than ours, so the Java we ship is always a version behind. This may not be the best way to do it.
10.7 Lion was the first release of Mac OS X with a Java Runtime Environment missing from the default install. Users could elect to install Java 6 as they needed using Apple's Software Update service, or download Java 7 directly from Oracle. As of June 18th, 2013 Mac OS X continues to receive Java security updates, but all of that is about to change.
Starting with OS X Mavericks Apple will no longer be providing a version of the Java Runtime Environment. Users who need Java will be prompted to download a version of Java 7 from Oracle's website. If you still need Java 6, you better stick with Mountain Lion.
A simple search for "Java Security" on the Web, reveals the real reason Apple is dropping Java. With a new versions of Java coming out every couple of weeks to fix severe security risks, it is no wonder Apple is taking a "coffee break."