I have a homework about implementing queues in java. I have written a code, but there is an error and I don't know how to fix it. Can please anyone help me with this?
Here is my code:
public class Radha {
    public int num;
    public Radha pas;
    public Radha(int num){
        this.num = num;
    }   
    public void shfaq(){
        System.out.println(num);
    }
    public static void main (String [] args){
        Radha x = new Radha(1);
        Radhe1 r = x.new Radhe1();
        r.enqueue(1);
        r.shfaq();
    }
    class Radhe1{
        public Radha koka;
        public Radha bishti;
        Radhe1(){
            koka.pas = null;
            bishti = koka;
        }
        public void shfaq(){
            Radha theLink = koka;
            while(theLink != bishti){
                theLink.shfaq();
                theLink = theLink.pas;
            }
        }
        public boolean bosh(){
            return(bishti == koka);
        }
        public int iPari (){
            if (bosh())
                System.out.println("radha eshte bosh");
                    return(koka.num);
        }
        public void dequeue(){
            if (bosh()){
                System.out.println("radha eshte bosh");
            }
            else{
                koka = koka.pas;
            }
        }
        public void enqueue(int a){
            bishti = bishti.pas;
            bishti.num = a;
            bishti.pas = null;
        }
    }
}
 
     
    