Question

I am using an enum singleton that looks (somewhat) like this:

public enum mySingleton{

  INSTANCE;

  private static String myDrink = null;

  public String getMyDrink(boolean isWizard)
  {
    if (myDrink == null)
    {
      if (isWizard)
        myDrink = "Butterbeer";
      else
        myDrink = "Whiskey";
    }
    return myDrink;
  }

 //Some more functionality
 //...
}

Now, to test this singleton i have a few tests that use it. But since all the test run one after the other in the same thread, once i run the first test, myDrink is set for all the other tests.

I don’t like that.

I was thinkin of using an @After function and use reflection to do set myDrink to null.

Iv’e tried this:

Field f = mySingleton.class.getField("myDrink");
f.setAccessible(true);
f.set(String.class, null);

But i get a java.lang.NoSuchFieldException.

How can it be done?

Answer 1

The myDrink field shouldn’t be static. Make it a non-static field, and then use

f.set(mySingleton.INSTANCE, null);

Also, use getDeclaredField instead of getField. getField looks for public fields.

If you can’t change it to non-static, then the first argument is ignored, so just use

f.set(null, null);