Singleton

Reports singleton classes.

Singleton classes are declared in a way that only one instance of the class can ever be instantiated. Singleton classes complicate testing, and their presence may indicate a lack of object-oriented design.

Example:

  class Singleton {
    private static final Singleton ourInstance = new Singleton();

    private Singleton() {
    }

    public Singleton getInstance() {
        return ourInstance;
    }
  }

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.

Singleton

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 | Class structure

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 Singleton

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