CODEWITHSUNDEEP
javamultithreading
sp00m
sp00m

Reputation: 48817

One "Java context" per thread?

Is it possible to launch a Java program from another Java program, just as if I were launching it using another Java command? When calling the main() method of a program from another program directly, the Java context is common to these both executions. I'm trying to have one Java context per thread.

Illustration:

src/com/project/ProjectLauncher.java

public class ProjectLauncher {

    static {
        PropertyConfigurator.configure("log4j.properties");
    }

    public static void main(String[] args) {
        Logger.getLogger(ProjectLauncher.class).info("started!");
        // Logs well as expected.
    }

}

test/com/project/TestProject.java

public class TestProject extends TestCase {

    public void testProject() {
        ProjectLauncher.main(null);
        Logger.getLogger(TestProject.class).info("tested!");
        // The above line logs well, while log4j has been initialized in ProjectLauncher.
        // I would like it to need its own initialization in this class.
    }

}

I tried to launch the main method in another thread/runnable, but the logger is still initialized by ProjectLauncher.

Upvotes: 0

Views: 108

Answers (1)

Jatin
Jatin

Reputation: 31724

Well when you start a Java process, its a new Instance of JVM. If you wish to start another JVM instance, then you need to start a separate process of it.

i.e.

    List<String> command = new ArrayList<String>();
    command.add("java");
    command.add("ProjectLauncher");
    ProcessBuilder builder = new ProcessBuilder(command);
    builder.redirectErrorStream(true);
    final Process process = builder.start();
        try {
           process.waitFor();
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        //if you wish to read the output of it then below code else you can omit it.
        InputStream is = process.getErrorStream();
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        String line;
        while ((line = br.readLine()) != null) {
            Logger.getLogger(MyClass.class.getName()).severe(line);
        }

Above we are ultimately starting a new process which in reality is java ProjectLauncher. In case if the class is not already compiled, then you will have to compile it similar to above but using javac instead of java and ProjectLauncher.java instead of ProjectLauncher etc.

Upvotes: 2

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