java 模拟一个栈

堆栈的特点：先进后出

public class Stack {  
        public static void main(String[] args) {  
            StackTools tools = new StackTools();  
            tools.add("a");  
            tools.add("b");  
            tools.add("c");  
            tools.add("d");  
              
          //  tools.remove();  
        }  
}
 
private class  StackTools {  
    private LinkedList<String> linkedList;  
    public StackTools(){  
        linkedList = new LinkedList<String>();  
    }  
      
    public void add(String string){  
        linkedList.addFirst(string);  
    }  
      
    public void remove(){  
        for(int i = 0; i < linkedList.size(); i++){  
                String content = linkedList.get(i);  
                System.out.println(content);  
            }  
    }  
          
}