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Double brace initialization

Reports Double Brace Initialization.

Double brace initialization may cause memory leaks when used in a non-static context because it creates an anonymous class that will reference the surrounding object.

Compared to regular initialization, double brace initialization provides worse performance since it requires loading an additional class.

It may also cause failure of equals() comparisons if the equals() method doesn't accept subclasses as parameters.

In addition, before Java 9, double brace initialization couldn't be combined with the diamond operator since it was incompatible with anonymous classes.

Example:

List<Integer> list = new ArrayList<>() {{ add(1); add(2); }};

After the quick-fix is applied:

List<Integer> list = new ArrayList<>(); list.add(1); list.add(2);

Inspection Details

By default bundled with:

IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,

Can be installed with plugin:

Java, 241.16690

Last modified: 29 April 2024