Why use JavaBean?

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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:

  • 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.

  • A JavaBean class should implement the java.io.Serializable interface. The Serializable interface 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 interface 
private int id;  // private property
private String name; // private property 
public User(){
  // no-argument constructor
} 
public void setId(int id){ // mutator method
  this.id=id;
}  
public int getId(){ // accessor method
  return id;
}  
public void setName(String name){ // mutator method
  this.name=name;
}  
public String getName(){ // accessor method
  return name;
}  
}

In the above code, we can see that:

  • The User class implements the java.io.Serializable interface.

  • All properties of the class are set to private.

  • Each property has a getter and setter method.

  • And the constructor has no argument at all.

Why Java Bean?

  • 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.

  • 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).

  • We can expose JavaBean events, properties, and methods to another application.

  • Even though JavaBeans are designed to run on the client-side, one can develop server-side beans.

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