Static class variables

The static keyword held a very special place in my mind as programmer. The concept spans across languages, like Java, C#, Javascript and even Python (!).

The Singleton pattern

My first actual useful usage of the static class attribute in Java was when back in the day, I was implementing the Singleton design pattern. A typical implementation looks like this:

public class ClassicSingleton {
    private static ClassicSingleton defaultInstance;

    private ClassicSingleton() {
        // do the math here
    }

    public static ClassicSingleton getInstance() {
        if (ClassicSingleton.defaultInstance == null) {
            ClassicSingleton.defaultInstance = new ClassicSingleton();
        }

        return ClassicSingleton.defaultInstance;
    }
}

This by-the-book implementation declares a static variable on the class ClassicSingleton and initializes it, when the getInstance() method is called.

A more Java-esoteric implementation would be the following:

public class EsotericSingleton {
    private static EsotericSingleton defaultInstance;

    static {
        defaultInstance = new EsotericSingleton();
    }

    private EsotericSingleton() {
        // do the math here
    }

    public static EsotericSingleton getInstance() {
        return defaultInstance…