// n = how often to compile my own source code
static void warmUpJavaCompiler(int n) {
  File srcDir = makeTempDir();
  File classesDir = makeTempDir();
  try {
    saveTextFile(newFile(srcDir, "main.java"), myJavaSource());
    for (int i = 1; i <= n; i++) {
      //print("Attempt " + i);
      compileWholeDir(srcDir, myLibraryFiles(), classesDir);
    }
  } finally {
    deleteDirectory(srcDir, false, false);
    deleteDirectory(classesDir, false, false);
  }
}

Began life as a copy of #1011222