static File javaCompile(S src) {

  ret javaCompile(src, "");

}

// returns path to classes dir

static synchronized File javaCompile(S src, S dehlibs) {

  S javaTarget = null; // use default target

  //print("Compiling " + l(src) + " chars");

  Class j = getJavaX();

  if (javaTarget != null)

    setOpt(j, "javaTarget", javaTarget);

  //setOpt(j, "verbose", true);

  File srcDir = cast call(j, "TempDirMaker_make");

  S className = getNameOfPublicClass(javaTok(src));

  S fileName = className + ".java";

  File mainJava = new File(srcDir, fileName);

  //print("main java: " + mainJava.getAbsolutePath());

  saveTextFile(mainJava, src);

  File classesDir = (File) call(j, "TempDirMaker_make");

  new L<File> libraries;

  Matcher m = Pattern.compile("\\d+").matcher(dehlibs);

  while (m.find()) {

    S libID = m.group();

    //print("libID=" + quote(libID));

    assertTrue(isSnippetID(libID));

    libraries.add(loadLibrary(libID));

  }

  try {

     // This seems to be empty in case of success with Eclipse compiler.

     S compilerOutput = cast call(j, "compileJava", srcDir, libraries, classesDir);

     if (nempty(compilerOutput)) print("Compiler said: " + quote(compilerOutput));

      // sanity test

      if (!new File(classesDir, className + ".class").exists())

        fail("No class generated (" + className + ")");

  } catch (Exception e) {

    //e.printStackTrace();

    fail("Compile Error\n" + getOpt(j, "javaCompilerOutput"));

  }

  ret classesDir;

}