push and pop

import java.util.*;
class Stack
{
int top;
int maxsize = 5;
int[] Stack_array = new int[maxsize];
Stack()
{
top = -1;

}
boolean isempty()
{
return(top<0);
}
boolean push(int val)
{
if(top == maxsize -1)
{
System.out.println("Stack Overflow!!");
return false;
}
else
{
top++;
Stack_array[top]=val;
return true;
}
}
boolean pop()
{
if(top==-1)
{
System.out.println("Stack Underflow!!");
return false;
}
else
{
System.out.println("nIteam popped:"+Stack_array[top-1]);
return true;
}
}
void display()

{
System.out.println("Printing Stack Elements....");
for(int i = top; i>0; i--)
{
System.out.println(Stack_array[i]+" ");
}
}
}
public class main{
public static void main (String[] args)
{
Stack stck = new Stack();
System.out.println("Initial Stack Empty:"+stck.isempty());
stck.push(10);
stck.push(20);
stck.push(30);
stck.push(40);
System.out.println("After push operation");
stck.display();
stck.pop();
System.out.println("After pop operation");
stck.display();
stck.pop();
System.out.println("After deletion");
stck.display();
}
}