A clone is an exact copy of the original. In java, it essentially means the ability to create an object with similar state as the original object. The java clone method. Object Cloning in Java. The object cloning is a way to create exact copy of an object. The clone method of Object class is used to clone an object. The ble interface must be implemented by the class whose object clone we want to create. is protected by its definition, so, practically, child classes of Object outside the package of the Object class can only.
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Java clone best practices 1. What is Java clone?
So cloning is about creating the copy of original object. Its dictionary meaning is: So, JVM when called for cloning, do following things: If the class has only primitive data type members then a completely new copy of the object will be created and the reference to the new object copy will be returned.
Object cloning in java the class contains members of any class type then only the object references to those members are copied and hence the member references in both the original object as well as the cloned object refer to the same object.
Apart from above default behavior, you can always object cloning in java this behavior and specify your own.
Java clone - deep and shallow copy - copy constructors
This is done using overriding clone method. Java Cloneable interface and clone method Every object cloning in java which supports cloning of objects has its own rules and so does java. In java, if a class needs to support cloning it has to do following things: You must implement Cloneable interface.
You must override clone method from Object class. Cloneable interface is broken in java Java docs about clone method are given below formatted and extract.
The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression: Second statement suggest that original and cloned objects should have same class type, but it is not mandatory.
Third statement suggest that original and cloned objects should have be equal using equals method, but it is not mandatory.
Our first class is Employee class with 3 attributes — id, name and department.
Java clone – deep and shallow copy – copy constructors
Not only has obj1 been copied, but the objects contained within it have been copied as well. We can use Java Object Serialization to make a deep copy.
Unfortunately, this approach has some problems too detailed examples. It's better to use Defensive copyingcopy constructors as egaga reply or static factory methods.
What is object cloning in Java?
Another disadvantage is object cloning in java one often cannot access the clone method on an abstract type. Most interfaces and abstract classes in Java do not specify a public clone method.
As a result, often the clone method can only be used if the actual class of an object is known, object cloning in java is contrary to the abstraction principle of using the most generic type possible. For example, if one has a List reference in Java, one cannot invoke clone on that reference because List specifies no public clone method.