How to launch an app from Java in Mac OSX?

Question

I would like to launch another application from my Java code which will run on OS X. Doesn anyone know how to do this? I think it involves the "Runtime.getRuntime.exec()" method, but I'm not sure how to tell it which application to launch.
Thanks

Answer 1

I dont know about OSX but i can give you a generalized
solution. In all OS's there will be a way to get to
command prompt. It is not really true: MacOS is one noticeable exception! Version 9, like every previous one, was completely extraneous to the notion of "command prompt", because the Macintosh, since its origin to nowadays, has been a "fanatically" User-Centric system: everything is iconic. A side effect of this approach is that MacOS was a pretty hard platform for low-level developers...
In MacOSX things have dramatically changed: this OS is a powerful Unix-like one, with the beautiful dress that only a Mac can wear: and finally, all you Mac users, here it is: the shell!
Of course, in MacOSX (and in MacOS "classic" too) there are paths and executable files.
MacOS1-9 file-system was a very peculiar one: resource fork and data fork for every file, ":" as path components separator (but what "common" user has ever seen a Macintosh path?) and so on.
MacOSX will use an Unix-like filesystem, I guess (I'm not a Mac user, I like every OS for its beauties - and therefore dislike Microsoft products even if often they give me bread).
But the key question is: how do I tell the runtime which file it has to execute?
Fortunately, every modern SO I know adopts a hyerarchical organization of its files. So, indipendently of what is considered the "root" ("C:\", "/" or whatever else), you can "trace" a relative path from your current path (if you use an Unix or URL idiom, "./") and the file you want to reach.
So, if your java app ("JavaApp.class") is placed in a folder called "MyJavaApp", nested in another folder called "Programs" that you see when you click on the "MacHD" icon, and you can manually launch the Mac app you're interested in clicking on an icon called "MyMacApp Program", placed in a folder called "MyMacApp", nested in another folder called "Programs" that you see when you click on the "MacHD" icon (it's the same folder we said before :-) ), using Unix or URL sintax we have that:
your java application is at: [...]/MacHD/Programs/MyJavaApp/JavaApp.class
the Mac application is at:
[...]/MacHD/Programs/MyMacApp/MyMacApp Program
The relative path from the former to the latter is, therefore:
../MyMacApp/MyMacApp
where two dots ("..") are the symbol for "parent folder".
If the situation is similar to above, the code to launch MyMacApp should be something like this:
import java.io.File;
File currentDir=new File("");
//supposing that double dot (..) is the symbol for "parent folder"
Runtime.getRuntime(
     new File(currentDir,".."
     +File.separator
     +"MyMacApp"
     +File.separator
     +"MyMacApp Program"
     ).getAbsolutePath()
in a more portable fashion - if you're not sure ".." works
(? who cares? we're launching a native app :-)) )
Runtime.getRuntime(
     new File(currentDir.getParent(),
     "MyMacApp"
     +File.separator
     +"MyMacApp Program"
     ).getAbsolutePath()
);Hope it works... good work!