How do I unmangle Windows filenames in Java?

Question

From Java, I'm extracting an executable into a location specified using File.createTempFile(). When I try to run my executable, my program hangs when it tries to read the first line of output.

I have discovered that if I try to run the same extracted executable from another program, it works if I specify the directory as C:\Documents and Settings\username\Local Settings\Temp\prog.exe. But if I specify the directory as C:\DOCUME~1\USERNA~1\LOCALS~1\Temp\prog.exe I get the hang.

Is there a way to unmangle the tilde filename in my program so I can specify a directory name that will work?

(And since I always like addressing the language and API design issues, is there any reason why Java File.createTempFile() and java.io.tmpdir have to evaluate to mangled filenames?)

Answer 1

You can use getCanonicalPath() to get the expanded path. E.g.:

try
{
  File file = File.createTempFile("abc", null);
  System.out.println(file.getPath());
  System.out.println(file.getCanonicalPath());
}
catch (IOException e) {}

... produces ...

C:\DOCUME~1\USERNA~1\LOCALS~1\Temp\abc49634.tmp
C:\Documents and Settings\username\Local Settings\Temp\abc49634.tmp

I tested this on XP, but assume it would work similarly on other Windows operating systems.

See @raviaw's answer to your second question.