Need to check JDK and install it using Swing

Question

Hi,
I need to develop a swing component where it has to automatically check in the users machine whether JDK is installed, if not it has to install the current version of JDK. Can any give some idea on how to move forward on this or any code would be helpful.
Thanks

Answer 1

Velasquez wrote:
I need to develop a swing component where it has to automatically check in the users machine whether JDK is installed, ..Why the JDK, as opposed to a JRE?
Also, why no [Duke stars|http://wikis.sun.com/display/SunForums/Duke+Stars+Program+Overview] offered for this thread? Is it not important to you?
Velasquez wrote:
..if not it has to install the current version of JDK. Can any give some idea on how to move forward on this or any code would be helpful.An earlier reply mentioned how to get the Java version for the currently running JRE. The [java.library.path, java.ext.dirs & sun.boot.class.path|http://pscode.org/prop/all.html?prop=java.library.path%2Cjava.ext.dirs%2Csun.boot.class.path]* properties might help you determine if that JRE is part of a JDK. For most developers running a Java application, that would be the case.
* I checked those properties in an application and each one mentioned 'JDK' somewhere, but that will probably never appear in any applet.
OTOH, I took an entirely different, and much simpler, route when developing the STBC. It is a compiler that requires the tools.jar of the JDK - which is not normally available to applets or webstart applications. Since this tool was aimed at developers, and they can get a JDK free from Sun, I simply offer them a file chooser to browse to the JDK they have already installed.
There was another option that I considered and rejected as 'too much work'. Go to the root directory of the JRE (having got the path from properties) and then go to the parent directory. If both JDKs and JREs are installed, they should hopefully all be under the one directory tree. Then look at the file names for each directory listed, searching for jdk and the string that determines version. Very hackish, but if you can implement it, I guess it would serve for 95% of the time (though I would prompt the user about installing a new JDK and instead offer them a file chooser in case their JDK is hidden somewhere else).
Don't be too afraid to pop a dialog to ask the user for help. After all, if the user is running the program, and it asks them to 'help it to help them', it is not as if they are going to refuse. Most developers (for example) would prefer to be asked than risk having some 'automagic' tool go off and make wrong decisions that they cannot control.