TIOBE - Java Coding Standard

Rule: Optimization11

Synopsis:	Avoid double brace initialization
Language:	Java
Severity Level:	5
Category:	Optimization

Description:

Double brace initialization is a pattern to initialize objects, such as collections, concisely. However, it implicitly generates a new .class file, and the object holds a strong reference to the enclosing object. For those reasons, it is preferable to initialize the object normally, even though it’s verbose.

Set<String> countries = new HashSet<String>() { // violation
    {
       add("India");
       add("USSR");
       add("USA");
    }
};