In Java, constructor refers to a block of code which is used to initialise an object. It must have the same name as that of the class. Also, it has no return type and it is automatically called when an object is created.
There are two types of constructors:
Default Constructor: In Java, a default constructor is the one which does not take any inputs. In other words, default constructors are the no argument constructors which will be created by default in case you no other constructor is defined by the user. Its main purpose is to initialise the instance variables with the default values. Also, it is majorly used for object creation.
Parameterized Constructor: The parameterised constructor in Java, is the constructor which is capable of initialising the instance variables with the provided values. In other words, the constructors which take the arguments are called parameterized constructors.