How to manage Linux file permissions in Java?

Question

Is there any mechanism to get and set the file/directory permissions?

For example, I want to show the permisssions of a file in a shell way:

-rwxr-xr--

Is it possible to do this using Java?

I know that there are some methods in the File class to know if the file canExecute, canRead and canWrite, but AFAIK this info is for the current user only. I need to know the whole octal number, for example 755, so I need to get it from the user, from group and from others.
I know that Java7 brings Posix operations, but how could do this using a smaller JRE?
I would like not to use a command like ls, or chmod.

Can you use third party libraries? – Joni Mar 22 '13 at 15:37 — Joni, Mar 22 '13 at 15:37

score 1 · Accepted Answer · answered Mar 22 '13 at 15:47

If you can use external libraries, there are several:

If an entire library seems a hassle, creating a JNI wrapper that calls the lstat C function and returns the access mode takes you about 10 minutes. Here's a tutorial that creates such a wrapper for the isatty and ttyname functions.

score 0 · Answer 2 · answered Mar 22 '13 at 11:02

0

As you say, in Java7, the JVM supports it, so you have a guarantee that this can be done portably in all OSs (because the JVM implementation takes care of it). Under Java7, you'd have to use a native library per OS you want to support. This is potentially even dirtier than executing chmod

answered Mar 22 '13 at 11:02

Miquel

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So, what is the answer? No, you can't do it? – Daniel Peñalba Mar 22 '13 at 11:07
@DanielPeñalba right. To the best of my knowledge, pre-Java7, your best option is executing `chmod` if you are in linux. But wait a bit, other people might know better! – Miquel Mar 22 '13 at 11:10

How to manage Linux file permissions in Java?

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