Why use JavaBean?
In this shot, we will learn about JavaBean and why we use them when building Java applications.
To understand why we use JavaBean, we first need to know what a JavaBean is.
A JavaBean is a Java class that follows a certain standard:
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JavaBean class properties should be set to
private– accessing /mutating these properties is done using getters/setters methods. -
A JavaBean class should have a public no-argument constructor.
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A JavaBean class should implement the java.io.Serializable interface. The
Serializableinterface allows the saving, storing, and restoring of a JavaBean’s state while in use.
There is no syntactic difference between a regular Java class. The standard stated above is what differentiates an ordinary Java class from a JavaBean class.
Example JavaBean class
Let’s see an example of a simple JavaBean class.
package demo;public class User implements java.io.Serializable{ // implementing the Serializable interfaceprivate int id; // private propertyprivate String name; // private propertypublic User(){// no-argument constructor}public void setId(int id){ // mutator methodthis.id=id;}public int getId(){ // accessor methodreturn id;}public void setName(String name){ // mutator methodthis.name=name;}public String getName(){ // accessor methodreturn name;}}
In the above code, we can see that:
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The
Userclass implements thejava.io.Serializableinterface. -
All properties of the class are set to
private. -
Each property has a getter and setter method.
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And the constructor has no argument at all.
Why Java Bean?
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A fundamental principle of software development is “Don’t Repeat Yourself” (DRY); a JavaBean is a reusable software component that can be used all around a Java application, adhering to the DRY principle.
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Java is an Object-Oriented Programming (OOP) Language. A core concept of OOP is encapsulation. A JavaBean encapsulates many objects into a single object (the bean).
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We can expose JavaBean events, properties, and methods to another application.
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Even though JavaBeans are designed to run on the client-side, one can develop server-side beans.
