Stack implementation in Java

Stack.java

public class Element {
    private int value;
    private Element next;
    
    public Element(int value, Element next) {
        this.value = value;
        this.next = next;
    }
}

public class Stack {
    private int number;
    private Element head;
    
    public void push(int value) {
        head = new Element(value, head);
    }
    
    public int pop() {
        if(isEmpty()) return "Stack is empty, sorry.";
        int result = head.value;
        head = head.next;
        return result;
    }
    
    public boolean isEmpty() {
        return head == null;
    }
}