invalid method declaration; return type required

[AdRock952]

I am trying to create a linked list which is sorted using the predifined methods for the interface but using my own code to rewrite the mehtods.

I have come across a problem and so far i have 1 error when compliling

invalid method declaration; return type required

the line it is pointing to is this

public compare(E o1, E o2) {

here is the whole code

package linkedlist;

import java.util.*;
import java.util.SortedSet;

/**
 *
 * @author ag257
 */
public class LinkedList<E> extends AbstractCollection<E> implements SortedSet<E> {
    
    private MyGenericContainer<E> header;
    //private MyGenericContainer<E> bottom;
    private int cargo;
    private int numberContents;
    private int size;
    
    /** Creates a new instance of LinkedList */
    public LinkedList() {
        numberContents = 0;
        size = 0;
    }
    
    public LinkedList (E contents) {
        header = new MyGenericContainer<E> (contents);
        //bottom = new MyGenericContainer<E> (contents);
        numberContents = 1;
    }
    public void addNewContents (E contents) {
        MyGenericContainer<E> next = new MyGenericContainer<E> (contents);
        
        if (numberContents == 0) {
            header = next;
        }
        else {
                MyGenericContainer<E> current = header;
                for (int i = 1; i < numberContents; i++ ) {
                    current = current.getNext();
                }
                current.setNext(next);
                
        }
        numberContents++;
    }
    
    public int size() {
        return size;
    }
    
    public boolean isEmpty( ) {
        return header.next == null;
    }
    
    public SortedSet subSet(E fromElement, E toElement) {
    	
    }
    
    public SortedSet headSet(E toElement) {
    	
    }
    
    public SortedSet tailSet(E fromElement) {
    	
    }
    
    public E first() {
        if (isEmpty()) {
            throw new NoSuchElementException();
        }
        return header;
    }
    
    public E last() {
        if (isEmpty()) {
            throw new NoSuchElementException();
        }
        return header.next;
    }
    
    public Comparator<E> comparator() {
    	
    	return new Comparator<E>() {
    		
    		public compare(E o1, E o2) {
				return o1.getContents().compareTo(o2.getContents());
    		}
    		
    		public boolean equals(E obj) {
    			if(!(obj instanceof Comparator))
        			return false;
    			else
    				return true;
    		}
    	};
    }
    
    public Iterator<E> iterator() {
        return new Iterator<E>() {
            private MyGenericContainer<E> current = header;
            E valueReturned;
            private int counter = 0;
            
            public boolean hasNext() {
                if (counter >= numberContents){
                    return false;
                }
                else {
                    counter++;
                    return true;
                }
            }
            
            public E next() {
                valueReturned = current.getContents();
                current = current.getNext();
                return valueReturned;
            }
            
            public void remove() {
                throw new UnsupportedOperationException();
            }     
        };
    }
}

 

[Ascalonian]

public compare(E o1, E o2) {
                return o1.getContents().compareTo(o2.getContents());
            }

You are missing the return type there. You should have:

public [COLOR=red]int[/color] compare(E o1, E o2) {
                return o1.getContents().compareTo(o2.getContents());
            }