Java8 – Optional’s Overview with Examples

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Java8 – Optional’s Overview with Examples

We can reduce the chance of NullPointerException’s in Java using best practices –

Don’t return null’s from methods
Don’t pass null’s as arguments

You can also use java.lang.Optional. Java8 Optional formalises the approach used in other languages, and already existed in some Java libraries. Optional is simply an object wrapper.

Examples

My approach is similar style to my post Java8 – Streams Cookbook and have included a class with a number of examples using Optional

Here is our base model, without getters and setters -

class Bike {
    private Optional<Wheels> wheels;
    private String brand;
    
    public Bike(Optional<Wheels> wheels, String brand) {
        this.wheels = wheels;
        this.brand = brand;
    }
}

class Wheels {
    private String brand;
    private int spokes;
    
    public Wheels(String brand, int spokes) {
        this.brand = brand;
        this.spokes = spokes;
    }
}
class NoBikeException extends Exception {
	private static final long serialVersionUID = 1L;
}