How can I compile and run other java classes from within an application?

Question

Hello there everyone! I really hope that someone can help me. I am writing a program that must be able to compile and run other java classes that are in different files, much like development environments like Kawa or Forte allow you to do.
There has to be a way of doing this ( I hope!! ), but i can't seem to find it!!
I have tried using this command to compile:
Runtime.getRuntime().exec ("c:\\programs\\javac className.java");
...and this one to run:
Runtime.getRuntime().exec ("c:\\programs\\java className");
...but neither works!!! I can compile and run classes that are in the same file as my application, but I can't get it to work at all for files in different directories or files.
PLEASE, PLEASE, PLEASE help me - i've run out of ideas, and i need this to be working in 3 days!!!
Thank you very much for any help anyone can give me, I really appreciate it!! Thanks again!!
Adrian ( ...in distress!! )

Answer 1

public class JavaCompiler{
   public static void main(String[] args)throws Exception{ //sorry bout the laziness
      if(args == null || args.length != 1){
         System.out.println("Usage: java JavaCompiler MyClass.java");
         System.exit(0);
      String className = args[0];
      Runtime rt = Runtime.getRuntime();
      Process p = rt.exec("javac " + className); //consider setting cpath for this
      p.waitFor();
      //now try to run after it is done.
      p = rt.exec("java " + className.substring(0, (className.length() - ".java".length()));
      p.waitFor();
      //do some other stuff
}This should get you going. You may consider looking into the System.getProperty() method in order to determine the type of OS it is running on in order to findo out what command to run. I know that the sun tool listed above is nice, but by my understanding the sun tools provided are not guaranteed to stay the same. I'm no expert on this matter, but that is one of the reasons there is no API documentation for those tools. Also, I don't believe those tools come packaged with the JRE. (Of course if you are making an IDE it will be expected that the user has an sdk installed. Good luck with figuring this thing out.