Since the POJO class does not have strict rules for naming conventions, thus they are comparatively easier to read or write. The POJO class in java has gained popularity over the years due to the readability & reusability it provides in the program. The term POJO was introduced by Martin Fowler ( An American software developer) in 2000.The POJO class in java has been available since EJB 3.0 by sun microsystem.Įnterprise JavaBeans (or EJB) is a standard server-side component model for distributed business applications. They are commonly used for data transfer and encapsulation, and they can be used to facilitate communication between different layers of an application or between different components of a distributed system. POJO classes do not require any special classpath or dependencies, which makes them easy to develop, test, and maintain. POJOs are also referred to as free objects because they are not limited by any specific framework. POJO (Plain Old Java Objects) are Java objects that are not bound by any framework-specific restrictions or conventions, such as access modifiers or the need to implement Serializable interfaces. Introduction To Plain Old Java Object (POJO) It can be created with ease and used to produce readability and reusability in the code. In Java applications, POJOs provide a simple, flexible, and portable way to encapsulate data and behaviour.

They are frequently used in conjunction with frameworks like Hibernate or Spring to provide dependency injection, map data to databases, and represent data models in web development frameworks. Additional methods for manipulating the data may also be present. In POJOs, private member variables with public getter and setter methods are typical. It can be used to facilitate communication between various layers or components of a distributed system and encapsulates data and related behaviour. Next, let’s extend the example above by implementing the transition from one stage of a pizza order to another.Plain Old Java Object also known as POJO is a regular Java object with no special restrictions other than those forced by the Java Language Specification and does not require any classpath. We can define constructors, methods, and fields inside enum types, which makes them very powerful. The compiler will flag the comparison as an incompatibility error: We avoid this issue by using the “=” operator. This is because the values of the enum and the getStatus method coincidentally are the same however, logically the comparison should be false. If(testPz.getStatus() = ) Īs for compile-time safety, let’s look at an example where we’ll determine that an enum of a different type is equal by comparing it using the equals method.

Conversely, if we use the equals method, we will get a NullPointerException: if(testPz.getStatus().equals()) Either value can be null and we won’t get a NullPointerException. Furthermore, the “=” operator provides compile-time and run-time safety.įirst, we’ll look at run-time safety in the following snippet, where we’ll use the “=” operator to compare statuses. Since enum types ensure that only one instance of the constants exist in the JVM, we can safely use the “=” operator to compare two variables, like we did in the above example.

Pojo java meaning