Java implementation of a stack

Package zhangtingting; public class Stacktest {private object[] stack;//number of elements; private int size;///default length to public stacktest () {this (10);}//can also To set its own length, that is, capacity; Public stacktest (int len) {stack = new Object[len];}//returns the number of elements; public int size () {return size;}//Returns the length of the array, that is, the capacity; public int Capacity () {return stack.length;}//implementation dynamic array; public void ensurecapacity () {if (size () = Capacity ()) {object[] newstack = new Object[size () * 3/2 + 1]; System.arraycopy (Stack, 0, newstack, 0, size ()); stack = Newstack; }//into stack; public void push (Object o) {size++; ensurecapacity (); stack[size-1] = o;}//null; public Boolean IsEmpty () {return size = = 0;}//out stack; Public Object Pop () {///first to be empty; if (IsEmpty ()) {throw new ArrayIndexOutOfBoundsException ("cannot be null");} Object o = stack[--size]; Stack[size] = null; return o; public static void Main (string[] args) {stacktest stack = new Stacktest (3); string[] data = new string[] {"A", "B", "C"}; for (int i = 0; i < data.length i++) {Stack.push (data[i]); System.oUt.println (Data[i] + "");} System.out.println ("***********"); while (!stack.isempty ()) {System.out.println (Stack.pop () + "");}    }}