Accepts a list of strings containing parentheses, and checks if they are balanced or not

BalanceParen.java

import java.util.*;

public class BalanceParen {
  public static void main(String[] args) {
    System.out.println(isBalanced(")))))"));
  }
  
  private static boolean isBalanced(String input) {
    Stack<Character> stack  = new Stack<>();

    Map<Character, Character> braces = new HashMap<Character, Character>() {{
      put('(', ')'); put('[', ']'); put('{', '}');
    }};

    for(char ch : input.toCharArray()) {
      if(braces.containsKey(ch)) {
        stack.push(ch); // push open braces into stack
      } else {
        if(stack.isEmpty()) {
          return false; // if we have a close brace and stack is empty, return false
        }
        if(ch != braces.get(stack.pop())) {
          return false;
        }
      }
    }
    return stack.isEmpty();
  }
}

BalanceParen.scala

import scala.collection.mutable.Stack
import scala.collection.immutable.HashMap

object BalanceParen {
    def main(args: Array[String]) {
        args map { str => println(s"$str : ${isBalanced(str)}") }
    }
    def isBalanced(input: String): Boolean = {
        val stack = new Stack[Char]
        val brace = HashMap('(' -> ')', '[' -> ']', '{' -> '}')

	input map (( ch: Char ) => {
            if( brace contains ch ) stack push ch
            else {
                if( stack.isEmpty )                       return false
                if( brace.get(stack.pop) != Some(ch) )    return false
            }
        })
        return stack.isEmpty
    }
}