As you all know, in Java, a class provides the blueprint for objects, you create an object from a class. There are many different ways to create objects in Java.
Following are some ways in which you can create objects in Java:
1) Using new Keyword : Using new keyword is the most basic way to create an object. This is the most common way to create an object in java. Almost 99% of objects are created in this way. By using this method we can call any constructor we want to call (no argument or parameterized constructors).
2) Using New Instance : If we know the name of the class & if it has a public default constructor we can create an object –Class.forName. We can use it to create the Object of a Class. Class.forName actually loads the Class in Java but doesn’t create any Object. To Create an Object of the Class you have to use the new Instance Method of the Class.
3) Using clone() method: Whenever clone() is called on any object, the JVM actually creates a new object and copies all content of the previous object into it. Creating an object using the clone method does not invoke any constructor.
To use clone() method on an object we need to implement Cloneable and define the clone() method in it.
- Here we are creating the clone of an existing Object and not any new Object.
- Class need to implement Cloneable Interface otherwise it will throw CloneNotSupportedException.
4) Using deserialization : Whenever we serialize and then deserialize an object, JVM creates a separate object. In deserialization, JVM doesn’t use any constructor to create the object.
To deserialize an object we need to implement the Serializable interface in the class.
Serializing an Object :
Object of DeserializationExample class is serialized using writeObject() method and written to file.txt file.
Deserialization of Object :
5) Using newInstance() method of Constructor class : This is similar to the newInstance() method of a class. There is one newInstance() method in the java.lang.reflect.Constructor class which we can use to create objects. It can also call parameterized constructor, and private constructor by using this newInstance() method.
Both newInstance() methods are known as reflective ways to create objects. In fact newInstance() method of Class internally uses newInstance() method of Constructor class.
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