In this page, we will see the difference between constructor and method.

  • Difference between constructor and method in java

    There are many differences between constructors and methods. They are given below.

    Constructor Method
    A constructor is used to initialize the state of an object. A method is used to expose the behaviour of an object that means to perform some task.
    Constructor is invoked implicitly at the time of object creation. Method is invoked explicitly by the user when needed.
    Constructor name must be same as the class name. Method name may or may not be same as class name.
    Constructor must not have a return type. Method must have a return type.
    The java compiler provides a default constructor if you don't have any constructor. Method is not provided by compiler in any case.

    Example of defining constructor and method in the Java Class.

    class Student {
    	String studentName;
    	String studentAddress;
    	String studentNumber;
    	int rollNumber;
    
    	// default constructor
    	public Student() {
    		studentName = "John";
    		studentAddress = "Delhi";
    		studentNumber = "9836521456";
    		rollNumber = 12365485;
    	}
    
    	// parameterized constructor
    	public Student(String name, String address, String number, int roll) {
    		studentAddress = address;
    		studentName = name;
    		studentNumber = number;
    		rollNumber = roll;
    	}
    
    	// define method{ void is return type}
    	public void printDetail() {
    		System.out.println("Name :" + studentName);
    		System.out.println("Address :" + studentAddress);
    		System.out.println("Number :" + studentNumber);
    		System.out.println("Roll Number " + rollNumber);
    
    	}
    
    	//main method
    	public static void main(String[] args) {
    		Student student1=new Student();
    		student1.printDetail();
    		System.out.println("**************************");
    		//creating second object
    		Student student2=new Student("Ashutosh ","Lucknow","453535335",454);
    		student2.printDetail();
    	}
    }
    

    Output:
    Name :John
    Address :Delhi
    Number :9836521456
    Roll Number 12365485
    **************************
    Name :Ashutosh 
    Address :Lucknow
    Number :453535335
    Roll Number 454
    

What next?

The next topic is this keyword in java

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