application of a stack as a balanced parenthesis checker

In this programming assignment you are required to implement a stack using arrays. The purpose of the stack is to check an expression involving parentheses, braces, & brackets and determine whether they are balanced. That is, whether they are in proper order and all open parentheses (or, braces, or brackets) have corresponding closing ones. Write a Java program to solve this problem. The input to your program is a .java file that contain parentheses, braces, and brackets. You may assume that the program file does not have any commenting. That is, no parenthesis, brace, or bracket is commented out. Create a separate class for your stack and implement all stack related methods (like push(), pop(), etc.) in it. YOU ARE NOT ALLOWED TO USE STACK CLASS FROM JAVA API.