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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.


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

Available in:

IntelliJ IDEA 2023.3, Qodana for JVM 2023.3


Java, 233.SNAPSHOT

Last modified: 13 July 2023