java data structures - stack underlying implementation: array implemented push, pop, empty stack is determined

com.stack Package; 

/ ** 
* @auther strong Fu 
* @date 2020/2/13 - 12:45 
* / 
public class MyStack { 
    // We use the underlying stack array to store data 
    int [] Elements; 
    public MyStack ( ) { 
        elements = new new int [0]; 
    } 
    // element pressed 
    public void Push (int element) { 
        // create a new array 
        int [] = newArr new new int [elements.length +. 1]; 
        // the original elements of the array to the new array 
        for (int I = 0; I <elements.length; I ++) { 
            newArr [I] = elements [I]; 
        } 
        // the element to be added into the new array 
        newArr [elements.length] = element; 
        // replace it with a new array array 
        elements = newArr; 
    } 
    // remove the top element
    int POP public () { 
        // do not stack element 
        IF (elements.length == 0) { 
            the throw a RuntimeException new new ( "empty Stack IS"); 
        } 
        // remove the last element of the array 
        int element = elements [elements.length --1]; 
        // Create a new array 
        int [] = newArr new new int [elements.length-1]; 
        // process the other elements of the original array are placed in the last element of the new array 
        for (int i = 0; I <elements.length -. 1; I ++) { 
            newArr [I] = elements [I]; 
        } 
        // alternative array 
        elements = newArr; 
        // return the top element 
        return element; 
    } 
    // Check the top element 
    public int Pick () { 
        // no element in the stack 
        if (elements.length == 0) {
            throw new RuntimeException("stack is empty");
        }
        return  elements[elements.length-1];
    }
    //判断栈是否为空
    public boolean isEmpty(){
        return elements.length==0;
    }

}