problem with multithreading

   i tried the following code

package pack;
class newthread extends Thread {

  super("Demo Thread");
  System.out.println("Child Thread: " + this);
  start ( );
 }

public void run( ) {
  try {
    for(int i=5; i>0; i--) {
      System.out.println("Child thread " + i );
      Thread.sleep(500)
     }catch(InterruptedException e) {
   System.out.println("child interrupted");
  }
 System.out.println("Exiting Child Thread");
}
}

class extendthread {
  public static void main(String arg[]) {
    new newthread();

  try {
    for(int i=5; i>0; i--) {
      System.out.println("Main thread " + i );
      Thread.sleep(1000);
    }
     }
catch(InterruptedException e) {
   System.out.println("Main interrupted");
  }
  System.out.println("Exitin Main Thread");
}
}

and got following errors :---->

i:\JavaPrograms\pack\extendthread.java:4: illegal start of type
  super("Demo Thread");
  ^
i:\JavaPrograms\pack\extendthread.java:4: <identifier> expected
  super("Demo Thread");
                      ^
i:\JavaPrograms\pack\extendthread.java:5: <identifier> expected
  System.out.println("Child Thread: " + this);
                    ^
i:\JavaPrograms\pack\extendthread.java:6: invalid method declaration;
return type required
  start ( );
  ^
i:\JavaPrograms\pack\extendthread.java:9: 'class' or 'interface'
expected
public void run( ) {
       ^

i m using Java2 version 1.4 . i couldn't figure out why any of these
errors appeared
as of why did the compiler show error in line <
System.out.println("Child Thread: " + this); >

please elaborate why these errors appeared and of way/s to remove them

gonna be greateful
thanks