Your Comprehensive Java Roadmap for 2025

Java: A Brief Look

According to Java’s website, Java is “is a programming language and computing platform first released by Sun Microsystems in 1995.” Java is an object-oriented, class-based, general-purpose language widely used for coding applications and has been popular among developers for over 20 years. The compiled code of a Java application (called "bytecode") runs on most operating systems, including Windows, Mac OS, and Linux.

Java was created by Sun engineers known as the Green Team as a language for digital devices such as set-top boxes and televisions. However, the language was too complex for machines at the time, but it was an excellent fit for Internet programming. Java was first known as "Greentalk," then "Oak," and finally "Java."

There have been 19 versions of Java released thus far, with the 20th version slated for a March 2022 release.

Who Is a Java Developer?

A Java developer takes care of developing software and applications using Java programming. He/she collaborates with other software engineers and web developers to utilize Java for developing applications, websites, and more.

A Java developer needs to be active until the end of the whole development life cycle of a solution or product. A developer also needs to be capable of analyzing and identifying technical problems concerning Java language and should come up with efficient, workable solutions. 

Exception Handling 

In Java, exception means an event that interrupts the normal flow of events in a program. Exception handling is a method to handle runtime errors such as RemoteException, IOExcpetion, SQLException, etc. 

Multithreading

A thread in Java refers to a lightweight process demanding fewer resources to create and share the process resources. Multithreading means a process of executing two or more threads at one time for the utmost utilization of the CPU. 

Java Input Output 

Java input-output is a crucial concept while working on Java programming. It includes elements such as input, output, and stream. Input refers to the data we provide to the program, whereas Output is the data we receive from the program. Stream represents the sequence of flow of the data. 

Advanced Java

To take a giant leap in Java learning, you should be familiar with the following concepts: 

• Servlets
• Java Persistence API
• Java Database Connectivity 
• JAX-RS
• Thymeleaf
• Design patterns

Core Java

Core Java is used to build computing or desktop applications. It is essentially based on single-tier architecture. 

The Java Developer Roadmap

Let's explore the roadmap for becoming a full-stack Java developer. Full-stack developers can work equally well with front-end and back-end software (also called client-side and server-side, respectively), and this versatility puts them in high demand. Full-stack developers can do it all.

Note that this Java developer roadmap is not the only one available. There are many paths up the mountain, as the saying goes. However, this particular roadmap offers a balanced, comprehensive, and realistic approach.

Front-End Development

These tools and skills are the foundations upon which you will build the rest of your Java developer roadmap. You should master these fundamental web development tools:

• CSS
• HTML
• JavaScript
• TypeScript

You then need to familiarize yourself with Integrated Development Environments (IDE):

• Sublime Text 3
• Visual Studio Code IDE

And, of course, since you’re focusing on front-end development, you need to know front-end frameworks like:

• Angular
• React
• VueJS

Finally, you should become familiar with User Interface (UI) libraries like Bootstrap CSS and Material UI.

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Back-End Development

For starters, you obviously need to master Core Java, including Java 8 features, also known as Java functional programming.

Speaking of Java, back-end developers also need to learn Java build tools like:

• Gradle
• Maven

Like the front-end technology, back-end development has its IDEs:

• Eclipse IDE
• Intellij IDEA
• Spring Tool Suite

Back-end developers need to work with different databases, so they should become familiar with No SQL and relational databases like:

No SQL databases

• Apache Cassandra
• MongoDB
• RavenDB
• Redis

Relational databases

• MS-SQL Server
• MySQL
• Oracle
• PostgreSQL
• SQL Server

Cloud databases

• CosmosDB
• DynamoDB

Other necessary back-end technologies include:

Build DAO/Repository Layers

• JPA/Hibernate
• Spring Data JPA

Build REST APIs in Java

• Jersey REST Framework
• RestEasy Framework
• Spring Boot

Secure REST APIs using Spring Security

• Authentication
• JWT
• Role-based authorization

Mandatory Skills for Java Developers

• Linux: As most of the Java applications are server-side, they typically run on Linux servers. Hence, it is critical to learn some Linux commands and concepts related to various functions. 
• Data structures and algorithms: Data structures and algorithms are building blocks of any programming language. Data structures such as linkedin list, binary tree, hash table, queue, etc are important ones to learn.  
• Fundamentals of computer science: It is crucial to be aware of fundamentals before learning any language. It helps in creating robust web or software applications. 
• SQL: Learning SQL helps troubleshoot backend issues like a pro. 
• Git and Github: As a Java programmer it is extremely important to be familiar with Git and GitHub concepts. They are popular version control systems.

Build Tools

In order to build Java projects, you should be familiar with various build tools. Following are some of the tools for building your Java project: 

• Ant
• Maven
• Gradle

Servers

Deploying should be ready once you have developed your web application. Deploying happens on servers; hence, you should be aware of them. Following are some of the servers that you can use to deploy your web applications: 

• Weblogic
• WebSphere
• Jetty
• JBOSS
• Tomcat

Did You Know? 🔍

The average java developer salary in the United States is $88,475. Java developer salaries typically range between $68,000 and $114,000 yearly.

Java APIs

APIs are very important software components packed with the JDK. They generally include interfaces, user interfaces, and classes. They facilitate developers to integrate numerous websites and applications whilst offering real-time information. Following are some of the Java APIs to learn about:

• Java IO
• Java concurrency 
• Java collections framework 

Java Frameworks

Java has a broad ecosystem, which means that there are various frameworks and libraries for anything and everything. Some frameworks a Java developer should learn are as follows: 

• Hibernate
• Log4j
• JUnit
• Spring boot
• Spring

Testing

Testing is a critical skill for Java developers, especially integration testing, unit testing, and automation testing. JUnit and Mockito are two of the most famous unit testing and mock libraries. More advanced libraries, such as Robot Framework and Cucumber are also helpful in various cases. On the other hand, though Mockito is a vast library, other libraries can also be helpful such as EasyMock and PowerMock.   

Utility Libraries

From sending an HTTP request to parsing JSON, you will have libraries to perform almost anything in Java. Utility libraries such as Google Guava and Apache Commons are crucial for any Java developer as they optimally complement JDK libraries. 

ORM 

ORM means Object Relational Mapping. It is a middlemen application tool sitting between a web application and a database. It converts data between Java objects and database tables. Following are some of the ORM tools: 

• EclipseLink
• OpenJPA
• MyBatis
• TopLink

General Knowledge Development Skills for Your Java Developer Roadmap

• Learn about GIT and how to create a few repositories on GitHub. Make sure to share your coding with others. GIT is a valuable tool for version control and project management.
• Familiarize yourself with HTTP(S) protocol, request methods (DELETE, GET, OPTIONS, POST, PUT, PATCH).
• If you haven’t become a Google search expert, learn how, especially using advanced search techniques.
• Read up on algorithms and data structures.
• Learn about Docker and how to deploy projects in Docker containers.
• Learn Jenkins to help you master the concepts of Continuous Integration/Continuous Deployment (CI/CD).
• Project management software like Jira, to help track issues and bugs.

Deployment

The cloud is the future, so master deployment with:

• AWS Cloud
• Azure Cloud
• Google Cloud
• Heroku Cloud

Testing

Familiarize yourself with a handful of Behavior, Integration, Load, and Unit testing resources like:

• Assertj
• CitrusFramework
• Cucumber-jvm
• Gatling
• Hoverfly-java
• Mockserver
• Rest-assured
• Truth

Also, consider learning Selenium to cover end-to-end testing chores.

There are other resources you can tack on to your roadmap. For example, some roadmaps get tremendously complex and inclusive, adding elements such as Logging, Caching, Object-Relational Mapping (ORMs), API Clients, and Task Scheduling. But the above roadmap is a good fit for most aspiring Java developers; you can always add on more skills later!

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Java Developer Career Options

There are many Java-based developer career options to choose from. They include:

• Junior Developer: Consider this an entry-level position. Everyone starts here. Junior developers write, test, analyze, and debug code.
• Senior Developer: They oversee an entire project, write some code, and act as a liaison to management.
• Java Web Developer: This position typically emphasizes back-end development, and the developer is responsible for deploying and maintaining the code on the server’s side. Since many servers are moving to the cloud these days, developers should have experience and skills in coding within a cloud environment.
• Java Architect: Conventional architects design buildings. Java architects design and develop an application’s layout.
• Java EE Developer: These developers build and maintain enterprise-level software and typically get hired by big companies.
• Java Android Developer: The Android mobile operating system market share is considerably greater than iOS, so there’s a greater demand for professionals who can build or add features to Android-based apps.

How Would You Like a Cloud-Based Java Developer Career?

We’ve already touched on Java’s immense popularity, so why not shoot for a career as a Java developer with a focus on cloud computing? After all, cloud computing’s popularity is on the rise, so combining a massively popular programming language with today’s hottest new computing trend is a can’t lose proposition!

Simplilearn offers a Professional Certificate Program in Cloud Computing in collaboration with the University of California, Irvine. You will learn in-demand cloud computing skills around security, scaling, and building highly resilient infrastructure on the cloud.

Alternatively, you can explore a career in cloud architecture with Simplilearn’s Cloud Architect Master’s Program. The program teaches you how to master the architectural principles and services of the top cloud platforms, design and deploy highly scalable, fault-tolerant applications and develop skills to transform yourself into an AWS, Azure cloud, and GCP architect.

Simplilearn also offers many other Java-related programs, including Java Certification Training and Full-Stack Java Developer. So visit Simplilearn today and get locked into a rewarding and exciting career path!