A briefly overview to Java frameworks

When you have a look at Merriam Webster about the word framework you find the following explanations:

  • a basic conceptional structure
  • a skeletal, openwork, or structural frame

May you could think that libraries and frameworks are equal things. But this is not correct. The source code calls the functionality of a library directly. When you use a framework it is exactly the opposite. The framework calls specific functions of your business logic. This concept is also know as Inversion of Control (IoC).

For web applications we can distinguish between Client-Side and Server-Side frameworks. The difference is that the client usually run in a web browser, that means to available programming languages are limited to JavaScript. Depending on the web server we are able to chose between different programming languages. the most popular languages for the internet are PHP and Java. All web languages have one thing in common. They produce as output HTML, witch can displayed in a web browser.

In this article I created an short overview of the most common Java frameworks which also could be used in desktop applications. If you wish to have a fast introduction for Java Server Application you can check out my Article about Java EE and Jakarta.

If you plan to use one or some of the discussed frameworks in your Java application, you just need to include them as Maven or Gradle dependency.

Before I continue I wish to telly you, that this frameworks are made to help you in your daily business as developer to solve problems. Every problem have multiple solutions. For this reason it is more important to learn the concepts behind the frameworks instead just how to use a special framework. During the last two decades since I’m programming I saw the rise and fall of plenty Frameworks. Examples of frameworks today almost nobody remember are: Google Web Toolkit and JBoss Seam.

The most used framework in Java for writing and executing unit tests is JUnit. An also often used alternative to JUnit is TestNG. Both solutions working quite equal. The basic idea is execute a function by defined parameters and compare the output with an expected results. When the output fit with the expectation the test passed successful. JUnit and TestNG supporting the Test Driven Development (TDD) paradigm.

If you need to emulate in your test case a behavior of an external system you do not have in the moment your tests are running, then Mockito is your best friend. Mockito works perfectly together with JUnit and TestNG.

The Behavioral Driven Development (BDD) is an evolution to unit tests where you are able to define the circumstances the customer will accepted the integrated functionality. The category of BDD integration tests are called acceptance tests. Integration tests are not a replacement for unit tests, they are an extension to them. The frameworks JGiven and Cucumber are also very similar both are like Mockito an extension for the unit test frameworks JUnit and TestNG.

For dealing in Java with relational databases we can choose between several persistence frameworks. Those frameworks allow you to define your database structure in Java objects without writing any line of SQL The mapping between Java objects and database tables happens in the background. Another very great benefit of using O/R Mapper like Hibernate, iBatis and eclipse link is the possibility to replace the underlying database sever. But this achievement is not so easy to reach as it in the beginning seems.

In the next section I introduce a technique was first introduced by the Spring Framework. Dependency Injection (DI). This allows the loose coupling between modules and an more easy replacement of components without a new compile. The solution from Google for DI is called Guice and Java Enterprise binges its own standard named CDI.

Graphical User Interfaces (GUI) are another category for frameworks. It depends on the chosen technology like JavaFX or JSF which framework is useful. The most of the provided controls are equal. Common libraries for GUI JSF components are PrimeFaces, BootsFaces or ButterFaces. OmniFaces is a framework to have standardized solution for JSF problems, like chaching and so on. Collections for JavaFX controls you can find in ControlsFX and BootstrapFX.

If you have to deal with Event Stream Processing (ESP) may you should have a look on Hazelcast or Apache Kafka. ESP means that the system will react on constantly generated data. The event is a reference to each data point which can be persisted in a database and the stream represent to output of the events.

In December a often used technology comes out of the shadow, because of a attacking vulnerability in Log4J. Log4J together with the Simple Logging Facade for Java (SLF4J) is one of the most used dependencies in the software industry. So you can imagine how critical was this information. Now you can imagine which important role Logging has for software development. Another logging framework is Logback, which I use.

Another very helpful dependency for professional software development is FF4J. This allows you to define feature toggles, also know as feature flags to enable and disable functionality of a software program by configuration.

Name Category
JUnit, TestNG TDD – unit testing
Mockito TDD mocking objects
JGiven, Cucumber BDD – acceptance testing
Hibernate, iBatis, Eclipse Link JPA- O/R Mapper
Spring Framework, Google Guice Dependency Injection
PrimeFaces, BootsFaces, ButterFaces JSF User Interfaces
ControlsFX, BootstrapFX JavaFX User Interfaces
Hazelcast, Apache Kafka Event Stream Processing
SLF4J, Logback, Log4J Logging
FF4j Feature Flags

This list could be much longer. I just tried to focus on the most used ones the are for Java programmers relevant. Feel free to leave a comment to suggest something I may forgot. If you share this article on several social media platforms with your friends or colleagues I will appreciate.