compileClasses

lukeUCD

hey havin a prob with this piece of code below it basically is a java program that compiles another java file in it using compileClasses it compiles but it doesn't work as hello.java is not compiled,any help you could give would be great


import java.lang.Compiler;
import java.io.*;

public class TestCompile
{
public static void main(String[] args){


File f = new File("Hello.java");
System.out.println(f.isFile()); //test it is a file

//name of java file to be compiled
boolean b = Compiler.compileClasses("Hello.java");


if(b)
{
System.out.println("it worked");
}
else
{
System.out.println("it didn't");
}
System.out.println(b);
}
}


*****************
public class Hello
{
public static void main(String[] args)
{
System.out.println("hello");
}
}

aidan_walsh

Well, the first thought that comes to me is to put the compilation code in a seperate thread and have the calling thread wait until the compilation one is finished.

test999

"put the compilation code in a seperate thread and have the calling thread wait until the compilation one is finished."

would that make it work? :rolleyes:
just tell him what he's doing wrong, now,
and you can show off, later.

aidan_walsh

test999 wrote:

"put the compilation code in a seperate thread and have the calling thread wait until the compilation one is finished."

would that make it work? :rolleyes:
just tell him what he's doing wrong, now,
and you can show off, later.

Show off? I have seen problems that are overcome by seperating processes. There are occasions where it is necessary to put heavy duty tasks to a new thread and make the original one wait, because the program jumps onto the next step pre-emptively. So yeah, it might help it work.

Also, having read the documentation, I'm wondering if you are running this on an evoirnment that onlt has the JRE installed, as without the JDK, there is no installer to call. It might also be that the JDK isn't properly registered in the system, so that when the system is looking for the compiler, it can't find it and moves onto the next step.

Hobbes

Why not just use ANT? Or is there a reason your doing it that way?

lukeUCD

The code is to test if student's submitted code for homework excercises compile or not.

The problem seems to be that the System is not finding a compiler since System.getProperty("java.compiler") returns null.

Is there a way to manually specify what compiler it should be using (as there are jdk's installed - it just doesn't seem to find them)?

GreeBo

lukeUCD wrote:

The problem seems to be that the System is not finding a compiler since System.getProperty("java.compiler") returns null.

ok, so how about system.setProperty(java.compiler, theJITCompiler)?
do you have a JAVA_HOME environment variable?

MrPinK

doodle_sketch wrote:

There are occasions where it is necessary to put heavy duty tasks to a new thread and make the original one wait, because the program jumps onto the next step pre-emptively. So yeah, it might help it work.

If the method call was non-blocking then that would mean that a seperate thread was being kicked off in the method already. But it would be very unusual for a method to be non-blocking when it's supposed to be returning a boolean indicating success or failure.