balanced parentheses in an expression

class balanced_parentheses_in_an_expression
{
  public static void main(String[] args)
  {
     String input= "[()]{}{[()()]()}";  
     reverse(input);
  }
  static String input= "[()]{}{[()()]()}";
  static int l=input.length();
  static char array[]=new char[l];
  static int top=-1;
  static char stackarray[]=new char[l];
    
  static void reverse(String input)
  {
     for (int j = 0; j < l; j++) 
     {
         char ch = input.charAt(j);
         if(ch == '{' || ch == '(' || ch == '[')
             {
               
                 push(ch);
             }
         if(ch == '}' || ch == ')' || ch == ']')
             {
                 if(top == -1)
                 {                     
                      System.out.println(" expression is un balanced ..");
                      System.exit(1);
                 }
                 
               pop(ch);
                       
             }
         
      }
      if(top!=-1)
      {
           System.out.println(" expression is un balanced ..");
                     System.exit(2);
      }
       System.out.println(" expression is  balanced ..");
  }
     public static void push(char value)
    {
         top++;
          stackarray[top]=value;                       
    }
    
    public static void pop(char ch)
    {
        
        if(top>=0)
        {                
            if( (ch==')')&&(stackarray[top]=='(') || (ch==']')&&(stackarray[top]=='[') || (ch=='}')&&(stackarray[top]=='{') )
            {
               
                 top--;  
            }
            else
            {
                 System.out.println(" expression is un balanced ..");
                      System.exit(1);
            }
                
        }
    }
    
}