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

Inspection Details
By default bundled with:	IntelliJ IDEA 2024.3, Qodana for JVM 2024.3,
Can be installed with plugin:	Java, 243.26483

01 April 2025