What modifiers may be used with an inner class that is a member of an outer class?

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A (non-local) inner class may be declared as public, protected, private, static, final, or abstract.

In Java, an inner class that is a member of an outer class can have various modifiers. The modifiers that can be applied to an inner class include:

  1. Access Modifiers:
    • public: The inner class can be accessed from outside the outer class.
    • protected: The inner class can be accessed within the package and by subclasses.
    • default (no modifier): If no modifier is specified, the inner class is accessible only within the package.
    • private: The inner class is only accessible within the outer class.
  2. Static Modifier:
    • static: If the inner class is static, it is associated with the outer class rather than with instances of the outer class. Static inner classes cannot access non-static members of the outer class directly.
  3. Abstract Modifier:
    • abstract: Inner classes can be abstract if they do not provide a complete implementation and need to be subclassed.
  4. Final Modifier:
    • final: An inner class marked as final cannot be subclassed.
  5. Strictfp Modifier:
    • strictfp: Inner classes can be marked as strictfp to ensure strict floating-point precision.

Here’s an example of an inner class with modifiers:

java
public class OuterClass {

private int outerField;

public class InnerClass {
// Inner class members

// Example with modifiers
public static final int CONSTANT_VALUE = 10; // static and final
protected void innerMethod() {} // protected method
}

// Outer class members
}

In this example, InnerClass is a non-static inner class with the public access modifier. It also contains a static final field and a protected method. The choice of modifiers depends on the desired visibility and behavior of the inner class in relation to the outer class and other classes.