How to use and implement useContext()

1. Using a new keyword.

- It's the most popular one. We create an object by using a new operator followed by a constructor call.

Exemple : 

class ClassA{

}
ClassA obj = new ClassA()

2. newinstance() method

- Using the newInstance() method of class "Class"

Exemple  : 

class ClassA {

}
ClassA obj = ClassA.class.newInstance();

3. newinstance() method - 2

- Using the newInstance() method in class "Constructor".

Exemple : 

class ClassA {

}
Constructor<ClassA> obj = ClassA.class.getConstructor().newInstance(); 

- Both the previous ways (Shown in 2 and 3), are known as reflective ways of creating objects.

Fun-fact:

- Class's newInstance() method internally uses Constructor's newInstance() method.

4. clone method

- Using "Object" class clone() method. The clone() method creates a copy of an existing object.

- The clone) method is part of the "Object" class which returns a clone object.

- Example:

public class ClassA implements Cloneable {
protected Object clone() throws CloneNotSupportedException {
//.....
}
}
ClassA obj1 = new ClassA( );
ClassA obj2 = (ClassA) obj1.clone();

- When using the clone() method:

- Always Remember:

•  The "Cloneable" interface is implemented.
•  The clone() method must be overridden with other classes.
•  Inside the clonel() method, the class must call super.clone().

5. Deserialization

- When we deserialize any object then JVM creates a new object internally.

For this, we need to implement the Serializable interface.

- Example:

public class ClassA implements Serializable{
//...
}

// Serialization
ClassA classA ; 
try( 
ObjectOutputStream in = new ObjectOutputStream( new FileOutputStream("class.obj"))){
out.writeObject(classA);
}

//Deserialization
ClassA deserialClassA ; 
try ( ObjectInputStream in = new ObjectInputStream(new FileInputStream("classA.obj"))){
deserialClassA = (classA) in.readObject() 
}

//desrialClassA Object will be created after deserialization process