Compiling a Java class using JavaCompiler

19 April 2008

Java 6 introduces a way to compile Java classes from a Java class. In this post, I will present an example to show how this is done.

I have a Test.java file:

public class Test{
 
public static void main(String[] args) {
        // TODO code application logic here
        System.out.println("Hello World");
callMe();
}
    public static void callMe(){
     System.out.println("Hello Babar dost");
    }
}

I want to compile it from my Java class. This is possible in Java 6 using javax.tools package. Lets see how this is done:

import javax.tools.*;
import java.io.*;
import java.util.Arrays;
 
public class Main {
 
    public static void main(String[] args) {
 
        File file = new File("C:\\Test.java");
 
        File files1 = file ; // input for first compilation task
       JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
       StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
 
       Iterable<? extends JavaFileObject> compilationUnits1 =
           fileManager.getJavaFileObjectsFromFiles(Arrays.asList(files1));
       compiler.getTask(null, fileManager, null, null, null, compilationUnits1).call();
    }
}