Question

So I did read the tread of what and when static initalizer is executed from this thread. Static initializer in Java. But I am running into some old code written by someone else and can’t seem to understand why he would use it the way he did.

My Class:

public class ClassA extends Thread {
  .... private vars ....

  private static Config config;

  static {
    config = null;
  }

  public ClassA(Config config) {
    ClassA.config = config;
  }
}

Why didn’t he just do this?

public class ClassA extends Thread {
  .... private vars ....

  private static Config config = null;

  public ClassA(Config config) {
    ClassA.config = config;
  }
}

I understand that static initalizer gets call as the class being redenered, so it sets config => null, while if i don’t use static initalizer, instance variables get initalizer right before the constructor, and right after super. So wouldn’t the two class be doing the same thing?

Answer 1

These classes are doing the same thing, but more complex static initializers can’t always be done on a single line.