Define, compile and run dynamic code in RAM

jMDA provides a feature to conveniently define Java source code as String, to compile the content of such a String and finally run the compiled byte code. The following example demonstrates how to do this. The code and everything else necessary to compile and run the example is available here.

package de.jmda.sample.ramcomp;

import java.io.IOException;

import de.jmda.core.util.ramcomp.RAMCompiler;

import de.jmda.core.util.ramcomp.RAMCompiler.RAMCompilerData;

public class DefineCompileAndRunJavaSourceCodeInRAM

{

  public static void main(String[] args)

      throws InstantiationException,

             IllegalAccessException,

             ClassNotFoundException,

             IOException

  {

    RAMCompilerData data1 =

        new RAMCompilerData

        (

"C1",

"public class C1 implements Runnable           \n" +

"{                                             \n" +

" public void run()                            \n" +

" { System.out.println(getClass().getName()); }\n" +

"}"

        );

    RAMCompilerData data2 =

        new RAMCompilerData

        (

"C2",

"public class C2 implements Runnable           \n" +

"{                                             \n" +

" public void run()                            \n" +

" { System.out.println(getClass().getName()); }\n" +

"}"

        );

    RAMCompiler.compile(data1, data2);

    Object object;

    // run first class

    object =

        data1.getClassLoader()

             .loadClass(data1.getQualifiedTypeName()).newInstance();

    ((Runnable) object).run();

    // run second class

    object =

        data2.getClassLoader()

             .loadClass(data2.getQualifiedTypeName()).newInstance();

    ((Runnable) object).run();

  }

}

The above example demonstrates that it is easily possible to define and compile even multiple Java source code strings at the same time. After compiling the code you can run each program using standard Java reflection.