10 Best Java Frameworks to Use in 2021

Java is a robust language and when combined with a framework, Java can provide the best solutions for any domain be it e-commerce, banking, cloud computing, finance, big data, stock market, IT, and more.

A body of pre-written code acting as a template or skeleton, which a developer can then use and reuse to create an application by filling in their code as needed to get the app to work as they intend refers to as a Framework. Reuse of frameworks enables developers to program their application without the manual overhead of creating every line of code from scratch.

With its concept of Dependency Injection and aspect-oriented programming features, Spring took the development world by storm. It is an open-source framework used for Enterprise applications.

With Spring, developers can create loosely coupled modules where-in dependencies are handled by the framework rather than depending on the libraries in the code.

Spring framework is exhaustive and covers a lot of features including security and configuration, which are easy to learn. Further, since it is the most popular web framework, you can find a lot of documentation and an active community.

Though Hibernate is not a full-stack framework, it completely changed the way we looked at the database. Implementation of Java Persistence API (JPA), Hibernate is an Object-Relational-Mapping (ORM) database for Java applications. Just like SQL, queries in Hibernate are called HQL (Hibernate Query Language).

Hibernate directly maps Java classes to corresponding database tables and vice versa.

Don’t confuse JSF with JSP, which is just a text document that can have static and dynamic content. JSF is developed by Oracle as a part of the Java Enterprise Edition 7.

It is a component-based MVC framework and has reusable UI components for server-based applications. The main idea is to encapsulate various client-side technologies like CSS, JavaScript, and HTML that will allow developers to create UI without knowing any of these technologies in-depth. They can just drag and drop UI components and focus more on their presentation layer specifics.

The default templating system in JSF is the FaceLets. JSF is quite similar to Struts.

Play is a slightly conventional and unique type of framework that follows the approach of convention over configuration. It is based on the MVC pattern and is an open-source web application framework. Apart from Java, you can write Play web applications in Scala.

Play is similar to Django or Ruby on Rails or ASP.NET architecture and doesn’t necessarily follow J2EE web standards.

Though Apache Hadoop is not a full-stack framework, it provides a software framework and works on the MapReduce programming model. These utilities can easily handle huge volumes of data (Big Data), store, analyse and process them to provide faster and more efficient results.

I have included Hadoop in this list because it is the ‘thing’ of today with Big Data gaining prominence.

Hadoop helps in distributed data storage and processing using the master slave design pattern. The Hadoop HDFS (Hadoop Distributed File System) layer of the master node (namely NameNode) has the data node. The MapReduce layer has the JobTracker and the tasktracker. The slave nodes have the Data node and the taskTracker respectively.

Another masterstroke from Apache, Spark is an open-source web development framework which has similar features as Spring, Play and JAX-RS, but is more powerful and doesn’t follow the traditional MVC design pattern.

It is a micro-framework and a domain-specific language for Java focussing on the speed of development. It needs very less configuration and coding. It is 10 times faster than Hadoop in terms of data processing because of in-memory computation. A completely dynamic framework, Spark supports lazy initialization and real-time data processing.

Developed by Eclipse, Vert.x is an event-driven application framework that uses many languages like Java, JS, Groovy, Scala and more. It is thus polyglot in nature. It relies upon the asynchronous programming model thus making the applications non-blocking and free from multi-threading.

Vert.x can be said as more of a toolkit that provides APIs in multiple languages to perform asynchronous tasks that all the web applications need – logging, authentication, monitoring, DB connectivity, multi-cluster support etc… There are 2 main concepts in Vert.x –

Jersey is a web services framework to create RESTful services and supports JAX-RS APIs. It greatly simplifies the development of RESTful services through useful features and utility functions. Jersey provides a sort of abstraction layer so that developers need not worry about the low-level implementation of client-server communication and can concentrate on the main web service functionality.

A striking feature of Jersey, as opposed to any other RESTful frameworks, is that it allows for Chunked output i.e. the server can send back a response to a client in parts or chunks. This is useful when a large data has to be sent and data chunks can be sent while the entire response is prepared.

Drools is a popular Business Rules Management System. It has a Business Rules Engine (BRE), authoring, a rules management application and runtime support for Decision and Notation models. The rules management app is called as the Drools workbench. The project is backed by RedHat and JBoss. With Drools, developers can easily separate the data from business logic. The two main steps in Drools are –

Authoring – Creation of rule files

Runtime – where you execute the rules

The most important feature of Drools is that new rules can be removed and added at any time without restarting the server.

OSGi or Open Service Gateway initiative defines a component-based system. It is a popular Java framework where each component is called a bundle. Each bundle has an independent lifecycle and is not dependent on other bundles. Consider the bundle to be jar file with OSGi-specific headers. Bundles have to explicitly declare the packages they need access to without which the OSGi platform will not start.

Bundles use the JVM-level service registry to discover, publish and bind bundles as services. This is the essence of OSGi – for a modular application architecture promoting adaptability and quick changes without much application down-time (run-time flexibility).

OSGi is mainly popular because of its easy integration with eclipse and maven-based projects.