Skip to main content

Do not use Java double brace initialization

Medium
JavaClean code

Java double brace initialisation is an anti-pattern.

Cf. https://www.baeldung.com/java-double-brace-initialization

Disadvantages of using double braces are:

Obscure, not widely known way to do the initialization It creates an extra class every time we use it Doesn’t support the use of the “diamond operator” – a feature introduced in Java 7 Doesn’t work if the class we are trying to extend is marked final Holds a hidden reference to the enclosing instance, which may cause memory leaks

It’s due to these disadvantages that double brace initialization is considered as an anti-pattern.

Examples​

Example 1:​

Negative​

Incorrect implementation that violates the practice.


public class Main {
    public static void main(String[] args) {

        Order order = new Order() {{
            setReference("abc-123");
            setCustomer("John Doe");
        }};

    }
}