What is use of static inner class in Java?

If a class A is declared inside another class B then that class A is a nested class. If a nested class is marked static then it is called static nested class and if it not then it is called non-static nested class or inner class. There is nothing called top level static class or static inner class.

Is inner class a good practice?

Any additional encapsulation, such as making the entire inner class private , is desirable; but public inner classes are perfectly acceptable. There are many examples in Java, such as AbstractMap.

Should static classes be inner?

An inner class, by default, has an implicit reference to an object of the outer class. If you instantiate an object of this from the code of the outer class, this is all done for you. As a basic rule, if the inner class has no reason to access the outer one, you should make it static by default.

What are the advantages of inner classes in Java?

The main advantages of a nested (inner) class are:

• It shows a special type of relationship, in other words, it has the ability to access all the data members (data members and methods) of the main class including private.
• They provide easier code because it logically groups classes in only one place.

What is the advantage of static inner class?

The advantage of a static nested class is that it doesn’t need an object of the containing class to work. This can help you to reduce the number of objects your application creates at runtime. It’s called a nested class. All nested classes are implicitly static; if they are not static they are called inner classes.

What is a static inner class?

A static inner class is a nested class which is a static member of the outer class. It can be accessed without instantiating the outer class, using other static members. Just like static members, a static nested class does not have access to the instance variables and methods of the outer class.

Are inner classes bad?

Inner classes are frequently used, and something very similar – anonymous classes – are practically indispensable, as they are the closest thing Java has to closures. So if you can’t remember where you heard that inner classes are bad, try to forget about it! They’re not “bad” as such.

What is the difference between inner class and anonymous class in Java?

A local inner class consists of a class declared within a method, whereas an anonymous class is declared when an instance is created. So the anonymous class is created on the fly or during program execution.

Is static inner class thread safe?

We know static variables are not thread safe.

What are two advantages to using inner classes?

It helps in code optimization.

It requires less code to write.

It has nested classes which are used to develop more readable and maintainable code.

It logically group classes and interfaces in one place only.

It can access all the members (data members and methods) of outer class including private.

What are the advantages of using inner and anonymous classes?

The anonymous inner class has advantage over the inner class (as in the question example code) in that it closes over the local variables of the method (although only final locals are usable). Generally an inner class can be easily converted into a method with anonymous inner class, which helps reduce verbosity.

What are disadvantages of using inner classes?

Q7)What are disadvantages of using inner classes?

• Using inner class increases the total number of classes being used by the application.
• Inner classes get limited support of ide/tools as compared to the top level classes, so working with the inner classes is sometimes annoying for the developer.