// before you use this, add a RAM disk cleaner
sbool javaCompileToJar_useRAMDisk;

static File javaCompileToJar_optionalRename(S src, File destJar, S progID) {
  ret javaCompileToJar_optionalRename(src, "", destJar, progID);
}

// returns path to jar
static synchronized File javaCompileToJar_optionalRename(S src, S dehlibs, File destJar, S progID) {
  S javaTarget = null; // use default target
  
  //print("Compiling " + l(src) + " chars");
  S dummyClass = "main";
  if (progID != null) {
    dummyClass = dummyMainClassName(progID);
    src += "\nclass " + dummyClass + "{}";
  }
  S md5 = md5(src);
  File jar = destJar;

  Class j = getJavaX();
  if (javaTarget != null)
    setOpt(j, "javaTarget", javaTarget);
  //setOpt(j, "verbose", true);
  File srcDir = tempDir();
  S className = "main";
  S fileName = dummyClass + ".java";
  File mainJava = new File(srcDir, fileName);
  //print("main java: " + mainJava.getAbsolutePath());
  saveTextFile(mainJava, src);
  File classesDir = javaCompileToJar_useRAMDisk ? tempDirPossiblyInRAMDisk() : tempDir();
  //print("Compiling to " + f2s(classesDir));
  try {
    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));
    }
    
    libraries.add(pathToJavaxJar());
      
    S compilerOutput;
    try {
      compilerOutput = (S) call(j, "compileJava", srcDir, libraries, classesDir);
    } catch (Throwable e) {
      compilerOutput = (S) get(getJavaX(), "javaCompilerOutput");
      fail("Compile Error. " + compilerOutput + " " + e);
    }
    
    if (nempty(compilerOutput)) {
      print("Compiler said: " + compilerOutput);
      //fail("Compile Error. " + compilerOutput);
    }
  
    // sanity test
    if (!new File(classesDir, className + ".class").exists())
      fail("No class generated (" + className + ")");
        
    // add sources to .jar
    saveTextFile(new File(classesDir, "main.java"), src);
    
    // add information about libraries to jar
    if (nempty(dehlibs))
      saveTextFile(new File(classesDir, "libraries"), dehlibs);
  
    //print("Zipping: " + classesDir.getAbsolutePath() + " to " + jar.getAbsolutePath());
    dir2zip_recurse_verbose = false;
    int n = dir2zip_recurse(classesDir, jar); // cache on success only
    //print("Files zipped: " + n);
  
    ret jar;
  } finally {
    if (isInRAMDisk(classesDir)) deleteDirectory(classesDir);
  }
}