Why We Used Inner Classes In Java

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Nested Classes :
In Java , just like methods, variables of a class too can have another class as its member. Writing a class within another is allowed in Java. The class written within is called the nested class, and the class that holds the inner class is called the outer class.
Inner Classes (Non-static Nested Classes) :
Inner classes are a security mechanism in Java. We know a class cannot be associated with the access modifier private, but if we have the class as a member of other class, then the inner class can be made private. Best core java training in bangalore And this is also used to access the private members of a class.
Types Of Inner Class :
Inner classes are of three types depending on how and where you define them. They are [1] Inner Class
[2] Method-local Inner Class
[3] Anonymous Inner Class
Inner Class :
Inner class, we just need to write a class within a class. Unlike a class, an inner class can be private and once we declare an inner class private, it cannot be accessed from an object outside the class.
Method-local Inner Class :
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... In Java, we can write a class within a method and this will be a local type. Advanced java training in bangalore Like local variables, the scope of the inner class is restricted within the method.
A method-local inner class can be instantiated only within the method where the inner class is defined.
Anonymous Inner Class :
An inner class declared without a class name is known as an anonymous inner class. In case of anonymous inner classes, we declare and instantiate them at the same time. Generally, they are used whenever we need to override the method of a class or an interface.
Advantage of java inner classes :
They are as follows:
1) Nested classes represent a special type of relationship that is it can access all the members (data members and methods) of outer class including private. Java training center bangalore
2) Nested classes are used to develop more readable and maintainable code because it logically group classes and interfaces in one place only.
3) Code Optimization: It requires less code to write.
Why Use Nested Classes?
Compelling reasons for using nested classes include the following:
[1] It is a way of logically grouping classes that are only used in one place: If a class is useful to only one other class, then it is logical to embed it in that class and keep the two together. Nesting such "helper classes" makes their package more streamlined.
[2] It increases encapsulation: java course in bangalore Consider two top-level classes, A and B, where B needs access to members of A that would otherwise be declared private. By hiding class B within class A , A's members can be declared private and B can access them . In addition, B itself can be hidden from the outside world.
[3] It can lead to more readable and maintainable code: Nesting small classes within top-level classes places the code closer to where it is used.
Difference between nested class and inner class in Java :
Inner class is a part of nested class. Non-static nested classes are known as inner classes. java/j2ee classes bangalore
Internal working of Java member inner class
The java compiler creates two class files in case of inner class. The class file name of inner class is "Outer$Inner". If we want to instantiate inner class, we must have to create the instance of outer class. In such case, instance of inner class is created inside the instance of outer class.
Internal code generated by the compiler
The java compiler creates a class file named Outer$Inner in this case. The Member inner class have the reference of Outer class that is why it can access all the data members of Outer class including private. best java training institute bangalore Marathahalli

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