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2024.3

'while' loop spins on field

Warning
New
Last modified: 03 December 2024

Reports while loops that spin on the value of a non-volatile field, waiting for it to be changed by another thread.

In addition to being potentially extremely CPU intensive when little work is done inside the loop, such loops are likely to have different semantics from what was intended. The Java Memory Model allows such loops to never complete even if another thread changes the field's value.

Additionally, since Java 9 it's recommended to call Thread.onSpinWait() inside a spin loop on a volatile field, which may significantly improve performance on some hardware.

Example:

After the quick-fix is applied:

Use the inspection options to only report empty while loops.