static class CompilerBot {
  static bool verbose;

  static File compileSnippet(S snippetID) {
    ret compileSnippet(snippetID, "");
  }
  
  static Pair<File, S> compileSnippet2(S snippetID) {
    ret compileSnippet2(snippetID, "");
  }
  
  // returns jar path
  static File compileSnippet(S snippetID, S javaTarget) {
    ret compileSnippet2(snippetID, javaTarget).a;
  }
  
  // returns jar path, Java source
  static Pair<File, S> compileSnippet2(S snippetID, S javaTarget) {
    S transpiledSrc = getServerTranspiled2(snippetID);
    if (transpiledSrc == null) fail("Snippet not found or not public: " + snippetID);
    int i = transpiledSrc.indexOf('\n');
    String libs = transpiledSrc.substring(0, Math.max(0, i));
    if (verbose)
      print("Compiling snippet: " + snippetID + ". Libs: " + libs);
    transpiledSrc = transpiledSrc.substring(i+1);
    return pair(compile(transpiledSrc, libs, javaTarget, snippetID), transpiledSrc);
  }

  static File compile(S src) {
    ret compile(src, "");
  }
  
  static File compile(S src, S libs) {
    ret compile(src, libs, null);
  }

  static File compile(S src, S dehlibs, S javaTarget) {
    ret compile(src, dehlibs, javaTarget, null);
  }
  
  static File compile(S src, S dehlibs, S javaTarget, S progID) {
    if (verbose)
      print("Compiling " + l(src) + " chars");
      
    // Note: This is different from the calculation in x30
    // (might lead to programs being compiled twice)
    S md5 = md5(dehlibs + "\n" + src + "\n" + fsIOpt(progID));
    File jar = getJarFile(md5);
    if (jar == null || jar.length() <= 22) {
      // have to compile
      
      //print("Have to compile: " + progID + " / " + md5);
      
      LS tok = javaTok(src);
      LS mainClass = findMainClass(tok);
      bool canRename = mainClass != null && useDummyMainClasses() && isSnippetID(progID) && !tok_classHasModifier(mainClass, "public");
      if (verbose)
        print("useRenaming: " + useDummyMainClasses() + ", canRename: " + canRename + ", progID: " + progID);
        
      S mainClassName = joinNemptiesWithDot(tok_packageName(tok), or(getClassDeclarationName(mainClass), "main"));
      
      temp tempSetTL(javaCompileToJar_addMoreFiles, 
        dir -> {
          if (!eq(mainClassName, "main"))
            saveTextFile(newFile(dir, "main-class"), mainClassName);
          saveTextFile(newFile(dir, manifestPathInJar()), manifestTextForMainClass(mainClassName);
        });

      javaCompileToJar_optionalRename(src, dehlibs, jar, canRename ? progID : null, progID);
    } else {
      if (verbose)
        print("Getting classes from cache (" + jar.getAbsolutePath() + ", " + jar.length() + " bytes)");
      touchFile(jar); // so we can find the unused ones easier
    }
    
    ret jar;
  }

  // look in non-virtual JavaX-Caches first (important for packaged programs)
  // Edit: Huh? This is strange.
  static File getJarFile(S md5) {
    assertTrue(isMD5(md5));
    S fileName = md5 + ".jar";
    File f = newFile(destDir(), fileName);
    ret fileExists(f) ? f : userDir(appendSlash(compilerBotDestDirSubName()) + fileName);
  }
  
  /*swappable*/ static File destDir() {
    ret compilerBotDestDir();
  }
}

Began life as a copy of #1002203