Synthetic accessor call

Reports references from a nested class to non-constant private members of an outer class. For such references, javac will generate package-private synthetic accessor methods, which may compromise the security because members appearing to be private will in fact be accessible from the entire package.

A nested class and its outer class are compiled to separate class files. The Java virtual machine normally prohibits access from a class to private fields and methods of another class. To enable access from a nested class to private members of an outer class, javac creates a package-private synthetic accessor method.

By making the private member package-private instead, the actual accessibility is made explicit. This also saves a little bit of memory, which may improve performance in resource constrained environments.

This inspection only reports if the language level of the project or module is 10 or lower. Under Java 11 and higher accessor methods are not generated anymore, because of nest-based access control (JEP 181).

Example:

  class Outer {
    private void x() {}

    class Inner {
      void y() {
        x();
      }
    }
  }

After the quick fix is applied:

  class Outer {
    void x() {}

    class Inner {
      void y() {
        x();
      }
    }
  }

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.

PrivateMemberAccessBetweenOuterAndInnerClass

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.

Availability

By default bundled with: IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,
Can be installed with plugin: Java, 241.18072

Last modified: 18 June 2024