Executing a program within a program

[gibsonrocker800]

Hey guys. I am working on a project in which i need to execute javac inside. Basically, i want it so the user can enter java code, and then when they click a button, it compiles it. The thing is, i don't know how i can make it so that it executes javac. If anyone knows how to do this, please let me know.

[CaptainMorgan]

hey gibson. Most programming languages allow operating with child processes(ie: program within a program). Look into the class Runtime, specifically the exec method. I'm not sure how to apply javac, but you might find Runtime easier. Maybe... Runtime.exec("javac foo.java");

[gibsonrocker800]

Hm, well it's telling me that Runtime.exec can't be referenced from a static context, and i can now see that in the API because exec isnt a static method.

[jimm1]

Do this:

try{
Runtime.getRuntime().exec("javac foo.java");
}
catch(IOException e) {
e.printStackTrace();
}

The method "getRuntime()" returns the Runtime object associated with the current java application.
And the try-catch catches any IO exceptions thrown.

[gibsonrocker800]

Quote:

Originally Posted by jimm1

Do this:

try{
Runtime.getRuntime().exec("javac foo.java");
}
catch(IOException e) {
e.printStackTrace();
}

The method "getRuntime()" returns the Runtime object associated with the current java application.
And the try-catch catches any IO exceptions thrown.

Thanks man! Theres a problem though. It's not doing anything with javac or java... see like. I tried it out with like notepad and microsoft word and it executed them with no problem. Except, when i tried it out with javac Example.java ... It ran and compiled with no problem, but it didn't create the class file. I also tried it with like java Example.class and it didn't run it. Any solutions?

[Eku]

when compiling within a program. You need to Specify the classpath where you would like to put the class. example, in invoking the:

Code:

Runtime.getRuntime().exec("javac foo.java");

This is true, the compiling takes place and the "java foo.java" or calling the notepad will surely run. But, you didnt specify where the class file should be located. You can add it by invoking the -classpath function in javac. It may look more like this: (Putting the class in a single folder)

Code:

Runtime.getRuntime().exec("javac -classpath \"YourClassFolder\" \"Filepath\\foo.java\"");

Or if you want this: (putting the class in the same Folder)

Code:

Runtime.getRuntime().exec("javac -classpath \"FilePath\" \"Filepath\\foo.java\"");

^_^ God Bless in your code. I hope that helps.
Are you creating your own IDE? =)