'@Serial' annotation used on wrong member

Reports methods and fields in the Serializable and Externalizable classes that are not suitable to be annotated with the java.io.Serial annotation.

Examples:

class Test implements Serializable {
  @Serial // The annotated field is not a part of serialization mechanism because it's not final
  private static long serialVersionUID = 7874493593505141603L;

  @Serial // The annotated method is not a part of the serialization mechanism because it's not private
  void writeObject(ObjectOutputStream out) throws IOException {
  }
}

class Test implements Externalizable {
  @Serial // The annotated method is not a part of the serialization mechanism as it's inside Externalizable class
  private void writeObject(ObjectOutputStream out) throws IOException {
  }
}

For information about all valid cases, refer to the Javadoc of the java.io.Serial class.

Locating this inspection

By ID

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

serial

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

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

This inspection depends on the Java feature '@Serial annotation', which is available since Java 14.

New in 2020.3

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 serial

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