Serializable non-static inner class without 'serialVersionUID'

Reports non-static inner classes that implement java.io.Serializable, but do not define a serialVersionUID field.

Without a serialVersionUID field, any change to the class will make previously serialized versions unreadable. It is strongly recommended that Serializable non-static inner classes have a serialVersionUID field, otherwise the default serialization algorithm may result in serialized versions being incompatible between compilers due to differences in synthetic accessor methods.

A quick-fix is suggested to add the missing serialVersionUID field.

Example:

  class Outer {
      class Inner implements Serializable {}
  }

After the quick-fix is applied:

  class Outer {
      class Inner implements Serializable {
          private static final long serialVersionUID = -7004458730436243902L;
      }
  }

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 without 'serialVersionUID' 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