Welcome back friends, we are learning object oriented programming with Java. And here in this lecture we're going to start our journey with a class and object. So let's start. We all know that there are different objects. Referring to the same class, we can create multiple objects for the same class, that are also called as instances based on different cases or uses. A Java object is a self contained component, which consists of different methods and properties of the same class to make certain types of data useful, it has a specific value.

A class system allows the programmer to define various new classes that are also called as derived classes in terms of an existing class superclass, base class could be there and we can create multiple derived classes by using a technique called inheritance and we have overriding and augmenting so there are different objects referring to different classes. have multiple instances of same class. And each object could be used for different set of purposes. Let's understand here with an example. We have a class called student, which have two different variables, one of type integer and another of type string. Then we have the main function and within the main function, we have created an object of the of this class using the new keyword.

The object is called as s one. And we have s one.id and s one dot name to refer where we will have this class. We can display the values on the screen. We have class objects, we have class called animal and multiple objects referring to the same class. The objects could we review lighthouse, different species of animals. We have a lot We have Tiger we have elephant we have birds we have dogs, wolves, giraffe, ears, and more.

This is an example here we have a class called dog, which consists of different variables or parameters and different methods. A dog may have four different variables called breed, size, age and color, that define a species or particular dog and distinguish one dog from another. Similarly, a dog may have different set of methods or functions, color eat, sleep, set and run. So we can create different objects. Here we have three different objects, which can have different values assigned to different variables. And based on that variable we can perform which methods of operation to say the breed is Napoleon massive, and the size is large, easiest fibers and colors back.

This is an object Similarly, we can have a breed called car show, size and medium is three years colors around. So we have the same parameters defined in a class. And we have a specialized or specific method assigned to the instances or objects. The difference between class and object is very fine. We don't need to confuse an object as a state, in which all the properties have the value status either explicitly defined, or data defined by default settings. It could be defined or based on users.

It is difference between the class and object or church whereas a tendency we want to use them interchangeably of the context. There are different ways to create an object in Java, we can use a new keyword that we used earlier. In the example, we can also use the new instance method to create an object of the class. We can use the clone method also To create objects, we can use a DC realization. And we can have factory method being implemented to create objects. All of these are not important, we can get perfection over certain things simple would be most useful.

We can also create object called instances of the class, outside another class. I layer in earlier example, we have the main method placed right inside the class, where we are interested in creating the object. We can create object outside the class. The Student class is different, and we have different class crime student which has no relation with that class. But both are part of the same program, or same file. We can create testing.

There are generally three ways to initialize an object we have created an object And now we want to initialize or assign value. to different variables using the object. of the class. We can use a reference variable we can have a method. We can use by a constructor we can assign values based on these three mechanisms. First is initialization through the difference.

We can initialize an object variables of the class. By means of objects may or by storing data directly into the variable objects. In the class we have two variables say ID and Name of integer in a string types. We have different class, and we can create object of the same class and we can assign value. By using a reference we have object called as one of the student class. We can assign value to Id say 101.

If you want to assign a number, we can assign it by referencing object as one dot name of the variable that way. Similarly, we can assign the name as anything any string you want to assign. This is the first mechanism. Then we have different method say, we can initialize a value through methods. If a class have different methods, we can operate on various methods, the method may get or take input of based on different variables. Here we have two variables of type integer and name, we can pass values directly to this method.

The format of writing this will be the object name as one dot A main method of the class and pass the variables directly in within the braces separated by a comma or any delimiter. Then the third method is to initialize using the constructor It would be similar to using the method there could be multiple constructor are multiple methods of the same class. So, there are different objects an object that can be referring to different set of libraries I the object class is referring to Boolean character, class math runtime number, string system credit and through well different classes. So, we can perform various operations and we can we have to learn the different hierarchies things models might have been because of this could be denoted here. It could be used with all kinds of variables, data types, and methods in the class. The object methods of the class object class are different that we can use.

We can use finalize, we can use it close that creates a copy of the object if you want to create multiple objects having the same set of values. Ultimately when we can create a clone of existing object, we can have a high score to create suitable for putting the object into hash collection, which is a data structure. We can perform various tools for concurrency and locks, implementing of locks and file handling. You can have notify notify all wait wait that is a function of thread class, we're going to learn later, we can convert the text representation of the object to string we're using the to string method. Similarly, we have different classes. If we have the name of an object, and we want to learn about the class, we can use this method get class where we can get information about objects type or class.

Similarly, we can use the finalize method to call garbage collection that is the end of stuffs. So we are going to learn more in the coming lectures till then keep learning and keep moving ahead