!7

p-subst {
  File srcDir = makeTempDir();
  File classesDir = makeTempDir();
  try {
    saveTextFile(newFile(srcDir, "main.java"), myJavaSource());
    repeat 10 { time {
      compileWholeDir(srcDir, myLibraryFiles(), classesDir);
    }}
  } finally {
    deleteDirectory(srcDir, true, false);
    deleteDirectory(classesDir, true, false);
  }
}