MacOS – Multiple Java versions support on OS X and JAVA_HOME location

javamacos

I know is possible to have multiple versions of Java on OS X but i find it difficult to understand how it works.

I upgraded to Mountain Lion and now echo $JAVA_HOME is empty.

However in /System/Library/Frameworks/JavaVM.framework/Versions/

1.4     1.5     1.6     A       CurrentJDK
1.4.2   1.5.0   1.6.0   Current

When I go into 1.4.2 and I execute java - version or ./java -version

Java(TM) SE Runtime Environment (build 1.6.0_33-b03-424-11M3720)

So why all those versions are used for if they have same version of Java?

Then I downloaded the JDK 7 from Oracle and installed it.

Where a new JDK is usually installed?

And final question : How can I choose which version should run by default by all applications?

In Win. I set JAVA_HOME to the C:/ProgramFiles/Java/.…
I put in Path : location to JAVA_HOME/bin and that's it.

Best Answer

Contents of /System/Library/Frameworks/JavaVM.framework/Versions

For most use cases, CurrentJDK should provide the functionality of current and past versions of the JDK.

Not all past versions, but the versions most commonly required:

sh-3.2$ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.8
BuildVersion:   12A269
sh-3.2$ ls -l /System/Library/Frameworks/JavaVM.framework/Versions
total 64
lrwxr-xr-x  1 root  wheel   10 17 Jul 07:47 1.4 -> CurrentJDK
lrwxr-xr-x  1 root  wheel   10 17 Jul 07:47 1.4.2 -> CurrentJDK
lrwxr-xr-x  1 root  wheel   10 17 Jul 07:47 1.5 -> CurrentJDK
lrwxr-xr-x  1 root  wheel   10 17 Jul 07:47 1.5.0 -> CurrentJDK
lrwxr-xr-x  1 root  wheel   10 17 Jul 07:47 1.6 -> CurrentJDK
lrwxr-xr-x  1 root  wheel   10 17 Jul 07:47 1.6.0 -> CurrentJDK
drwxr-xr-x  8 root  wheel  272 17 Jul 07:48 A
lrwxr-xr-x  1 root  wheel    1 17 Jul 07:47 Current -> A
lrwxr-xr-x  1 root  wheel   59 17 Jul 07:47 CurrentJDK -> /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents
sh-3.2$

Related Solutions

MacBook – Java and Mac retina support

I just tested this on my MacBook Pro with retina, so the answer is yes and no - at least under Mountain Lion.

If you use Java directly from the command line, the answer is yes: it will launch in HiDPI and render text in high resolution. Things rendered using Graphics2D will render in high resolution mode. (So if you render a line 0.5 AWT pixels thick and place it at 0.25/0.75 off an AWT pixel, it will render a single "retinal pixel" thick.) Likewise, rendering an image at half-resolution will render it at "retinal" resolution.

So instead of just g.drawImage(image, x, y, observer) you'd need to do:

g.drawImage(image, x, y,
    image.getWidth(observer)/2,
    image.getHeight(observer)/2, observer);

(Unless you have an odd width/height, in which case you should probably use Graphics2D and just scale(0.5, 0.5) to render a retinal image.)

If you use JavaApplicationStub, then you need the answer provided by Matt Solnit, otherwise it will launch in the "scaled" mode. (Under Mountain Lion, there are added hoops to jump through related to Gatekeeper, but that's a different question.)

Note that this answer applies to both Mountain Lion and the Apple-provided version of Java for it (Java 1.6.0_33). It might be different under Oracle's Java 7 for Mac OS X, and it may not work the same way under Lion.

MacOS – Install Older Versions of Java on OSX 10.8.1

You simply cannot get arbitrary Java versions for the Mac. Apple provides their own Java binaries and does not provide every single Java release. Also, those old versions have known security problems with active exploits in the wild, so it's dangerous to use them on a desktop system.

My best recommendation would be to create a Linux VM using VMware Fusion and install the old versions either from the Linux package installer or using packages downloaded from Oracle.

Best Answer

Contents of /System/Library/Frameworks/JavaVM.framework/Versions

Related Solutions

MacBook – Java and Mac retina support

MacOS – Install Older Versions of Java on OSX 10.8.1

Related Question