Constructor is a special type of method that is used to initialize an object when it is created. Constructors have the same name as the class, and they are called when an object of that class is created using the new keyword.

Here are some key points to remember about constructors in Java:

1. 1. Constructors do not have a return type, not even void.
2. 2. Constructors can have parameters, which can be used to initialize the object's fields.
3. 3. A class can have multiple constructors, each with a different set of parameters. This is known as constructor overloading.
4. 4. If a class does not have any constructors defined, Java automatically provides a default no-argument constructor.
5. 5. You can use the this keyword to call another constructor in the same class, providing the flexibility to reuse code and initialize objects in different ways.
6. 
   

Here's an example of a class with a constructor:

public class Car {
    private int speed;
    private String model;

    // constructor
    public Car(int speed, String model) {
        this.speed = speed;
        this.model = model;
    }
}

And here's an example of how you might use the constructor to create an object:

Car myCar = new Car(60, "sedan");

It is important to note that the constructor is called automatically when an object is created, and it sets the initial values for the object's fields. In this way, constructors play a crucial role in the proper creation and initialization of objects in Java.