'ThreadLocal.set()' with null as an argument

Reports java.lang.ThreadLocal.set() with null as an argument.

This call does not free the resources, and it may cause a memory leak.

It may happen because:

Firstly, ThreadLocal.set(null) finds a map associated with the current Thread. If there is no such a map, it will be created
It sets key and value: map.set(this, value), where this refers to instance of ThreadLocal

java.lang.ThreadLocal.remove() should be used to free the resources.

Example:

  ThreadLocal<Integer> threadLocal = new ThreadLocal<>();
  threadLocal.set(null);

After the quick-fix is applied:

threadLocal.remove();

Locating this inspection

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Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

ThreadLocalSetWithNull

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Settings or Preferences | Editor | Inspections | Java | Threading issues

New in 2023.2

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection ThreadLocalSetWithNull

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

IntelliJ IDEA 2025.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.2, Qodana for JVM 2025.2,

Last modified: 18 September 2025