How to get File Permission Mode programmatically in Java

Question

I know it is possible to change the permission mode of a file using:

Runtime.getRuntime().exec( "chmod 777 myfile" );.

This example sets the permission bits to 777. Is it possible to set the permission bits to 777 programmatically using Java? Can this be done to every file?

Answer 1

Using chmod in Android

Java doesn't have native support for platform dependent operations like chmod. However, Android provides utilities for some of these operations via android.os.FileUtils. The FileUtils class is not part of the public SDK and is therefore not supported. So, use this at your own risk:

public int chmod(File path, int mode) throws Exception {
 Class fileUtils = Class.forName("android.os.FileUtils");
Method setPermissions =
  fileUtils.getMethod("setPermissions", String.class, int.class, int.class, int.class);
return (Integer) setPermissions.invoke(null, path.getAbsolutePath(), mode, -1, -1);
}

...
chmod("/foo/bar/baz", 0755);
...

Reference : http://www.damonkohler.com/2010/05/using-chmod-in-android.html?showComment=1341900716400#c4186506545056003185