Java Constructors

A constructor is a special method that initialises an object. It has the same name as the class and no return type, and it runs automatically when the object is created.

Types

Default (no-arg) constructor
Parameterized constructor

Java

class Emp {
    String name; int id;

    Emp() {                       // default
        name = "Unknown"; id = 0;
    }
    Emp(String name, int id) {    // parameterized
        this.name = name;
        this.id = id;
    }
    void show() { System.out.println(name + " " + id); }
}

new Emp().show();
new Emp("Neha", 101).show();

Unknown 0 Neha 101

NoteIf you write no constructor, the compiler supplies a default one. Once you write any constructor, it doesn't.

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