In workspace , when compiling it says :Introductions.java:10: error: reached ent file while parsing

import java.io.Console;

public class Introductions {

    public static void main(String[] args) {
        Console console = System.console();
        // Welcome to the Introductions program!  Your code goes below here
      console.printf("Hello,my name is String\n") ;
      console.printf("craig is learning how to write Java\n");        
    }

[MOD: edited code block - sh]

Yeah you are missing the last bracket at the very end.

import java.io.Console;

public class Introductions {

    public static void main(String[] args) {
        Console console = System.console();
        // Welcome to the Introductions program!  Your code goes below here
        console.printf("Hello,my name is String\n") ;
        console.printf("craig is learning how to write Java\n");        
    }
}

No problem - missing semi-colons, brackets, and spelling errors are some of the easiest mistakes to make when programming and they can be hard to catch sometimes. :p

Yes. Simply put // is the beginning of a line comment, anything after the // is ignored by the compiler - it is simply used to help the person writing the code to more clearly understand what is going on. There is also a multi-line comment which does the same thing but can span multiple lines, it looks like this:

/* This
* is a
* multi-line comment.
*/

It's essentially the only language for building Android apps. If your desire is to build Android apps then I think the best course of action would be take the Java Basics course and maybe the Java Objects course and then begin on the Android Development track.