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Double-checked locking

Reports double-checked locking.

Double-checked locking tries to initialize a field on demand and in a thread-safe manner, while avoiding the cost of synchronization. Unfortunately it is not thread-safe when used on a field that is not declared volatile. When using Java 1.4 or earlier, double-checked locking doesn't work even with a volatile field. Read the article linked above for a detailed explanation of the problem.

Example:

class Foo { private Helper helper = null Helper getHelper() { if (helper == null) synchronized(this) { if (helper == null) { helper = new Helper() } } } return helper; } }

Inspection options

Here you can find the description of settings available for the Double-checked locking inspection, and the reference of their default values.

Ignore double-checked locking on volatile fields

Not selected

Inspection Details

By default bundled with:

IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,

Can be installed with plugin:

Groovy, 241.16690

Last modified: 29 April 2024