Get system start time from RuntimeMXBean : RuntimeMXBean « Development « Java Tutorial

1. Java Tutorial
2. Development
3. RuntimeMXBean

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.Date;

public class Main {
  public static void main(String args[]) throws Exception {
    RuntimeMXBean mx = ManagementFactory.getRuntimeMXBean();
    System.out.println(new Date(mx.getStartTime()));
  }
}