Quick Answer: What Are Different Types Of Inner Classes?

Which are also known as inner classes?

Non-Static Nested Class (Inner Class) A non-static nested class is a class within another class.

It has access to members of the enclosing class (outer class).

It is commonly known as inner class ..

Can inner class final?

Inner class are defined inside the body of another class (known as outer class). These classes can have access modifier or even can be marked as abstract and final. Inner classes have special relationship with outer class instances.

Can abstract class have inner class?

It does not matter whether your class is abstract or concrete, as long as the nested class is either public , protected or the subclass is in the same package and the inner class is package private (default access modifier), the subclass will have access to it.

Can we make a class private?

No, we cannot declare a top-level class as private or protected. It can be either public or default (no modifier). If it does not have a modifier, it is supposed to have a default access.

Can we extend inner class in Java?

An inner class can be extended by another class outside of it’s outer class. If you are extending static inner class (Static nested class), then it is a straight forward implementation. … Because, you can’t access non-static inner class without the instance of outer class.

Do inner classes have to be static?

Technically, there is no such thing as a static inner class. According to Effective Java, the correct terminology is a static nested class. A non-static nested class is indeed an inner class, along with anonymous classes and local classes. … A static nested class does not have access to the enclosing instance.

What are non static inner classes?

Non-static nested classes are called inner classes. A nested class is a member of its enclosing class. Non-static nested classes (inner classes) have access to other members of the enclosing class, even if they are declared private. Static nested classes do not have access to other members of the enclosing class.

What is the difference between an inner class and a sub class?

inner classes are in the same file, whereas subclasses can be in another file, maybe in another package. You cannot get an instance of an inner class without an instance of the class that contains it. inner classes have the methods they want, whereas subclasses have the methods of their parent class.

Can a class be static?

So, Yes, you can declare a class static in Java, provided the class is inside a top-level class. Such clauses are also known as nested classes and they can be declared static, but if you are thinking to make a top-level class static in Java, then it’s not allowed.

What is local inner class?

Local Inner Classes are the inner classes that are defined inside a block. … These class have access to the fields of the class enclosing it. Local inner class must be instantiated in the block they are defined in. Rules of Local Inner Class: The scope of local inner class is restricted to the block they are defined in.

Can inner class have constructor?

Every Object (without any exceptions) is created by invoking a constructor. Here you can see that the compiler implements your inner class by declaring a final field member holding a reference to the enclosing class. … You can, though, do constructor chaining between other declared constructors of your inner class.

Can we declare local inner class as private?

Unlike a class, an inner class can be private and once you declare an inner class private, it cannot be accessed from an object outside the class. Following is the program to create an inner class and access it.

How many inner classes can a class have?

four typesInner class means one class which is a member of another class. There are basically four types of inner classes in java. Nested Inner class can access any private instance variable of outer class.

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.

What are inner classes and what are the types?

There are four types of inner classes: member, static member, local, and anonymous. A member class is defined at the top level of the class. It may have the same access modifiers as variables (public, protected, package, static, final), and is accessed in much the same way as variables of that class.