I want to install a specific JDK (the latest for example). For this, I went to the JDK download homepage: http://java.sun.com/javase/downloads/index.jsp. I looked for a Mac version, but I'm a bit surprised to only see downloadable versions for Linux, Windows and Solaris...
Here's the message for Mac:
"Apple Computer supplies their own version of Java. Use the Software Update feature (available on the Apple menu) to check that you have the most up-to-date version of Java for your Mac."
OK BUT... when I update Java with Mac I have a JRE and not a JDK...
I don't understand why a JDK version doesn't exist that is easily downloadable/installable (like a jar to unzip?) for Mac...
There are various tricky issues with having multiple versions of Java (Apple's own Java 6 and Oracle JDK 7 or even 8) on one's Mac OS X system, and using different versions for different applications. I spent some time writing up my experience of my experience of installing and configuring various versions of JDK on Mac OS X 10.9.2.
As of Mac OS X v10.6 (Snow Leopard), you can run Java 6 in 32-bit mode on either 32-bit or 64-bit Intel processor equipped Macs.
If you cannot upgrade to Snow Leopard, Soy Latte is a pre-compiled version of Java 6 for Intel 32-bit.
Check this awesome tool sdkman to manage your jdk and other jdk related tools with great ease!
e.g.
Compiling with -source 1.5 -target 1.5 (in a JDK 6 environment) will honor only language elements that were in 1.5 and prior. Great. But there were no language changes in 6 anyway. Problem with this approach (on Mac with 1.6) is that using classes that came AFTER 1.5 will still compile because they exist in the rt.jar. So one could run in a 1.5 env and get a class not found exception with no prior warning when compiling. I found this out the hard way with javax.swing.event.RowSorterEvent/Listener. Both entered "Since 1.6" but are not caught with -source 1.5
Mac comes with the JDK, for more information check:
http://developer.apple.com/mac/library/documentation/Java/Conceptual/Java14Development/02-JavaDevTools/JavaDevTools.html
As the message says, you have to go to Apple, not Sun, for Java on the Mac. As far as I know, Apple JDK 6 is installed by default on Mac OS X 10.6 (Snow Leopard). Maybe you need to install the developer tools from your Mac OS X installation DVD (the dev tools are an optional install from the OS DVD).
See: http://developer.apple.com/java/
NOTE This answer from 16 Oct 2009 is now outdated; you can get the JDK for Mac OS X from the regular JDK download page on Oracle's website now.