How to get UNIX uptime in Java?

Question

What is the best way to get the UNIX uptime in Java? Is there a standard Java library/function I could use or should I use Runtime's exec or ProcessBuilder to execute 'uptime'? Thanks

Answer 1

You can read /proc/uptime:

new Scanner(new FileInputStream("/proc/uptime")).next();
//"1128046.07" on my machine and still counting

From Wikipedia:

Shows how long the system has been on since it was last restarted:

$ cat /proc/uptime
  350735.47 234388.90

The first number is the total number of seconds the system has been up. The second number is how much of that time the machine has spent idle, in seconds.