How to define a class in Java?

by aliyah.nikolaus , in category: Java , 2 years ago

How to define a class in Java?

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2 answers

by jessyca_langosh , 2 years ago

@aliyah.nikolaus A java class definition can have the following 5 components

  1. Modifiers : A class can be public or has default access.
  2. Class name: The name should begin with an initial letter (capitalized by convention).
  3. Superclass(if any): The name of the class’s parent (superclass), if any, preceded by the keyword extends. A class can only extend (subclass) one parent.
  4. Interfaces(if any): A comma-separated list of interfaces implemented by the class, if any, preceded by the keyword implements. A class can implement more than one interface.
  5. Body: The class body is surrounded by braces, { }.

A sample class definition looks as shown below.

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public class Sample extends ParentClass implements SomeInterface
{
	//class body
}

B) Class Body

Java Class Body has two major components:

  1. Fields: These define the properties of an object and can also be used to differentiate a**** different objects of the same class. These also define the state of an object.
  2. Methods: These define the behavior of an object. The behavior may differentiate on the basis of the state or identity of an object of the same class.


Member

by schuyler , 8 months ago

@aliyah.nikolaus 

To define a class in Java, you'll need to follow these steps:


Step 1: Declare the class

  • Start by typing the access modifier (i.e., public, private, protected) followed by the keyword "class."
  • Then, specify the name of the class, starting with a capital letter.
  • For example: public class MyClass { }


Step 2: Declare class variables (optional)

  • Class variables are properties or attributes of the class that define its characteristics.
  • Declare these variables inside the class body but outside any method.
  • For example: private int age;


Step 3: Define class methods (optional)

  • Class methods are actions that can be performed by objects of the class.
  • Declare these methods inside the class body.
  • For example: public void printAge() { System.out.println(age); }


Step 4: Define a constructor (optional)

  • A constructor is a special method used to initialize objects of the class.
  • Declare it inside the class body using the same name as the class.
  • For example: public MyClass(int initialAge) { age = initialAge; }


Step 5: Add any other necessary code inside the class body

  • This can include additional methods, variables, constants, and more.


After defining the class, you can create objects (instances) of that class using the "new" keyword. For example:

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MyClass myObject = new MyClass();


With this, you can access the class variables and invoke the class methods using the object.