priority

http://stackoverflow.com/questions/297804/thread-api-priority-translation-to-os-thread-priority

Solaris

* 1 ⇒ 0
* 2 ⇒ 32
* 3 ⇒ 64
* 4 ⇒ 96
* 5 – 10 ⇒ 127

Of note is that on Solaris, you can't raise the thread priority above normal, only lower it: the priority value for 5 is the same as any of the higher values.
Linux

* 1 – 10 ⇒ 4 – -5 (nice values)

Of note is that on Linux, different thread priorities in Java do map to distinct priority values at native level.
Windows

* 1 – 2 ⇒ THREAD_PRIORITY_LOWEST
* 3 – 4 ⇒ THREAD_PRIORITY_BELOW_NORMAL
* 5 – 6 ⇒ THREAD_PRIORITY_NORMAL
* 7 – 8 ⇒ THREAD_PRIORITY_ABOVE_NORMAL

* 9 – 10 ⇒ THREAD_PRIORITY_HIGHEST

In linux , Is it overhead windows? I mean 10 is the highest priority in windows , But in linux , is it the lowest priority?

Another question:

http://www.javamex.com/tutorials/threads/priority_what.shtml

In this site there is a table that shows priorities in windows

Is this table is similar for all windows versions?

Dose anyone knows priority for different version of windows?(VISTA .7. XP and..)

The java thread priority is an abstraction of the OS thread priority. So if you set the java thread priority to the max it will (probably) create a thread with a high OS thread priority.
But the JVM doesn't guaranty that a thread with a high priority will get more cpu time then a thread with a low priority. It depends on the implementation.

Thread.setPriority(Thread.MAX_PRIORITY); is equal to thread.setPriority(10); on Windows platform, but what on some other platform? Is that equal for each OS or 10 could be different value on Unix, MacOS or whichever? How does Java map priorities?

Like I pointed about in my previous, apparently unclear, response. The java threading priority is an abstract of the os thread priority. So if you set thread.setPriority(10) then it will get a high priority on windows, linux, mac etc.

not all JVMs have the same number of priority levels

Is that correct?Do you know any Doc that justify this?

Look it up.