Serializable non-'static' inner class with non-Serializable outer class

Reports non-static inner classes that implement Serializable and are declared inside a class that doesn't implement Serializable.

Such classes are unlikely to serialize correctly due to implicit references to the outer class.

Example:

  class A {
    class Main implements Serializable {
    }
  }

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

Use the following options to configure the inspection:

List classes whose inheritors should not be reported by this inspection. This is meant for classes that inherit Serializable from a superclass but are not intended for serialization.
Whether to ignore Serializable anonymous classes.

Inspection options

Here you can find the description of settings available for the Serializable non-'static' inner class with non-Serializable outer class inspection, and the reference of their default values.

Ignore subclasses of: Default value:
[java.awt.Component]
Ignore anonymous classes: Default value:
Not selected

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