mammut@ubuntu:~/java$ java Calc
Exception in thread "main" java.lang.NoClassDefFoundError: Calc
   at gnu.java.lang.MainThread.run(libgcj.so.7)
Caused by: java.lang.ClassNotFoundException: Calc not found in gnu.gcj.runtime.SystemClassLoader{urls=[file:./], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}}
   at java.net.URLClassLoader.findClass(libgcj.so.7)
   at java.lang.ClassLoader.loadClass(libgcj.so.7)
   at java.lang.ClassLoader.loadClass(libgcj.so.7)
   at java.lang.Class.forName(libgcj.so.7)
   at gnu.java.lang.MainThread.run(libgcj.so.7)
mammut@ubuntu:~/java$ ls
Calc.java  Prior.class  PriorThread.class
mammut@ubuntu:~/java$

mammut@ubuntu:~/java$ cat Calc.java
import java.lang.Thread;

class PriorThread extends Thread
{
   static int count = 0;
   int id,mil;
    int max = 200000000;

   PriorThread(int millisek)
        {
         count++;
         id = count;
         mil = millisek;
        }

   public void run()
        {
         try {sleep (mil);} catch (Exception e) {}
         System.out.println("Thread nr." + id + " with priority " + getPriority() + " is starting");
         System.out.println("Thread nr." + id + " calculated " + work()+ "\n");
         if(id == 2)
            {
            System.out.println("\nChanging priority for Thread nr." + id + ". Priority is now  1\n");
            setPriority(1);
            }
         System.out.println("Thread nr." + id + " calculated " + work()+ "\n");
        }

   private float work()
        {
         int i,j;
         float res = 0;
         for(j=1;j<=3;j++)
             {
                 System.out.println("Thread nr." + id + " does work()");
                 for(i = 1;i < max;i++)
                     {
                         res += 1.0/(1.0*i*i);
                     }
             }
         return(res);
        }
}

class Prior
{
   public static void main(String args[])
   {
    System.out.println("\nStarts two threads !\n");
    PriorThread s1 = new PriorThread(1);
    s1.start();
    s1.setPriority(5);
    System.out.println("Default priority is " + s1.NORM_PRIORITY + " for a thread");
    System.out.println("Max is " + s1.MAX_PRIORITY + " and min is " + s1.MIN_PRIORITY + "\n");

    PriorThread s2 = new PriorThread(3000);
    s2.setPriority(10);
    s2.start();

   }
}
mammut@ubuntu:~/java$