A local class is declared locally within a block of Java code, rather than as a member of a class. Typically, a local class is defined within a method, but it can also be defined within a static initializer or instance initializer of a class.

What are local classes?

Local classes are classes that are defined in a block, which is a group of zero or more statements between balanced braces. You typically find local classes defined in the body of a method. This section covers the following topics: Declaring Local Classes. Accessing Members of an Enclosing Class.

What is the purpose of local class in Java?

You can define a java local class inside any block. For example, you can define a local class in a method body, a for loop, or an if clause. The main purpose of local inner class is to define logic that required instantly to use in local scope.

What is local class give example?

Local Class in C++



A class declared inside a function is known as a local class in C++ as it is local to that function. An example of a local class is given as follows. In the above example, func() is a function and class LocalClass is defined inside the function. So, it is known as a local class.

What is local inner class in Java with example?

A class i.e., created inside a method, is called local inner class in java. Local Inner Classes are the inner classes that are defined inside a block. Generally, this block is a method body. Sometimes this block can be a for loop, or an if clause. Local Inner classes are not a member of any enclosing classes.

How a local class differs from an inner class?

An inner class is just a class inside a class. A local class is an inner class declared inside of a block.

How do you create a local class?

To create object for the class we use the below two lines of code. START-OF-SELECTION. * Instantiate the Class/Create object for the class DATA: lo_demo TYPE REF TO lcl_demo. CREATE OBJECT lcl_demo.

What is local method in Java?

In Java, we can write a class within a method and this will be a local type. Like local variables, the scope of the inner class is restricted to the method. A method-local inner class can be instantiated only within the method where the inner class is defined.

What is local nested class?

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.

What is static class in Java?

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.

What is a singleton class in Java?

In Java, Singleton is a design pattern that ensures that a class can only have one object. To create a singleton class, a class must implement the following properties: Create a private constructor of the class to restrict object creation outside of the class.

What are inner classes in Java?

In Java, inner class refers to the class that is declared inside class or interface which were mainly introduced, to sum up, same logically relatable classes as Java is purely object-oriented so bringing it closer to the real world.

Is a static class a singleton?

A Singleton can implement interfaces, inherit from other classes and allow inheritance. While a static class cannot inherit their instance members. So Singleton is more flexible than static classes and can maintain state. A Singleton can be initialized lazily or asynchronously and loaded automatically by the .

Can we inherit static class?

Static classes are sealed and therefore cannot be inherited. They cannot inherit from any class except Object. Static classes cannot contain an instance constructor. However, they can contain a static constructor.

Can static class have constructor?

A static class can only have static members — you cannot declare instance members (methods, variables, properties, etc.) in a static class. You can have a static constructor in a static class but you cannot have an instance constructor inside a static class.

Can we inherit singleton class?

Unlike static classes, Singleton classes can be inherited, can have base class, can be serialized and can implement interfaces.

Can I extend singleton class?

All you need to extend a singleton class is a constructor with protected or package-default in the singleton class. If there are only private constructors you simply won’t be able to extend it. If there are public constructors then it’s not a singleton class.

Can a subclass be a singleton class?

Yes. A singleton class has a private constructor which is not accessible to any other class inside the same package or outside. Hence it cannot be sub classed from any other class.

How do you declare a singleton class in Java?

How to Create Singleton Class in Java

  1. Declaring all constructors of the class to be private.
  2. Providing a static method that returns a reference to the instance. The lazy initialization concept is used to write the static methods.
  3. The instance is stored as a private static variable.


Can constructor be private?

Yes, we can declare a constructor as private. If we declare a constructor as private we are not able to create an object of a class. We can use this private constructor in the Singleton Design Pattern.

What is immutable class in Java?

Java Immutable Class



In Java, when we create an object of an immutable class, we cannot change its value. For example, String is an immutable class. Hence, we cannot change the content of a string once created. Besides, we can also create our own custom immutable classes.

Why do we need singleton class?

The purpose of the singleton class is to control object creation, limiting the number of objects to only one. The singleton allows only one entry point to create the new instance of the class.

Why constructor is private in singleton?

In singleton class, we use private constructor so that any target class could not instantiate our class directly by calling constructor, however, the object of our singleton class is provided to the target class by calling a static method in which the logic to provide only one object of singleton class is written/ …

What is eager singleton?

Eager initialization: This is the simplest method of creating a singleton class. In this, object of class is created when it is loaded to the memory by JVM. It is done by assigning the reference an instance directly.