What is java pojo class, java bean, normal class?

1. Normal Class: A Java class that is normally create.
   
2. Java Beans:
   
   • All properties private (use getters/setters).
   • A public no-argument constructor.
   • Implements Serializable.
   • Java Beans are reusable software components for Java.
   • They are used to encapsulate many objects into a single object (the bean), so that they can be passed around as a single bean object instead of as multiple individual objects.
   • // Java program to illustrate JavaBeans

     class Bean

     {

         // private field property

         private Integer property;

         Bean()

         {

             // No-arg constructor

         }

       

         // setter method for property

         public void setProperty(Integer property)

         {

             if (property == 0)

             {

                 // if property is 0 return

                 return;

             }

             this.property=property;

         }

       

         // getter method for property

         public int getProperty()

         {

             if (property == 0)

             {

                 // if property is 0 return null

                 return null;

             }

             return property;

         }

     }

       

     // Class to test above bean

     public class GFG

     {

         public static void main(String[] args)

         {

             Bean bean = new Bean();

       

             bean.setProperty(0);

             System.out.println("After setting to 0: " +

                                      bean.getProperty());

       

             bean.setProperty(5);

             System.out.println("After setting to valid" +

                           " value: " + bean.getProperty());

         }

     } 
     Output:-
     

     After setting to 0: null
     After setting to valid value: 5

3. Pojo: Plain Old Java Object is a Java object not bound by any restriction . 

• Example of Pojo : 
• // Person POJO class to represent entity Person
  public class Person

  {

      // default field

      String name;

    

      // public field

      public String id;

    

      // private salary

      private double salary;

    

      //arg-constructor to initialize fields

      public person(String name, String id, 

                               double salary)

      {

          this.name = name;

          this.id = id;

          this.salary = salary;

      }

    

      // getter method for name

      public String getName()

      {

          return name;

      }

    

      // getter method for id

      public String getId()

      {

          return id;

      }

    

      // getter method for salary

      public Double getSalary()

      {

          return salary;

      }

  } 

  • Comparison between Java Bean Vs Pojo?
    

    POJO	Java Bean
    It doesn’t have special restrictions other than those forced by Java language.	It is a special POJO which have some restrictions.
    It doesn’t provide much control on members.	It provides complete control on members.
    It can implement Serializable interface.	It should implement serializable interface.
    Fields can be accessed by their names.	Fields are accessed only by getters and setters.
    Fields can have any visiblity.	Fields have only private visiblity.
    There can be a no-arg constructor.	It must have a no-arg constructor.
    It is used when you don’t want to give restriction on your members and give user complete access of your entity	It is used when you want to provide user your entity but only some part of your entity.