How long do my static variables live?

Question

I have a class that looks like:

  public class BadCodeStyle {

     private static String theAnswer = null;

     public static void setAnswer(String whatsNew) {
         theAnswer = whatsNew;
     }

     public static String getAnswer() {
          return (theAnswer == null) ? "I don't know" : theAnswer;
     }            

  }

Of course that's a simplification of the actual class. What really happens is that the static method retrieves a framework object if the variable is null. Setting the variable just serves to insert a mock value for test runs where I want to isolate the code from the framework (retrofitting code for testability is fun - like poking your own eye type of fun).

When I do BadCodeStyle.setAnswer("42") the static method behaves like a Singleton (?). I did read the classloader explanation and conclude: the variable will stay as long as the class is loaded and that would be as long as the JVM runs? Is that correct?

Answer 1

Static class variables live as long as the class definition is loaded. This is usually until the VM exits. However, there are other ways a class can be unloaded. See, for example, this thread and this one.