$PATH variable isn't inherited through getRuntime().exec

Question

I'm trying to start a script by the following command in Java:

proc = Runtime.getRuntime().exec(cmd, null, fwrkDir);

The command, typed in a console, works flawlessly. But here it doesn't seem to find the script, even though it's path is added to the $PATH variable. Doesn't Java automatically inherit all such variables, if null is passed as Environment?

Answer 1

proc = Runtime.getRuntime().exec(cmd, null, fwrkDir);

should be

proc = Runtime.getRuntime().exec(cmd, "PATH=$PATH:/android-sdk-linux_x86/platform-tools", fwrkDir);