Exposure to different subjects is good, but there are better, cleaner languages to use for introducing concepts of programming such as variables, functions, algorithms, and data structures without taking up students' attention with syntax and boilerplate that has nothing to do with the lesson being taught.

Compare these hello world programs for instance:

Java:

    public class HelloWorld {
         public static void main(String[] args) {
              System.out.println("Hello, world!");
         }
    }

Python:

    print "Hello, world!"

Ruby:

    puts 'Hello, world!'