How To Contribute To Open Source Java

Contributing to open source Java is simple with this step by step guide. Each topic has a link to the relevant documentation and some brief advice on what you can do to help. This guide builds on the process for submitting a patch, which you find at

This document provides a quick overview of the steps to contribute code to Apache projects; in particular, it focuses on contributing to Apache Harmony. It is assumed that you are somewhat familiar with the Java programming language and have general knowledge of the Apache development process. The information in this document applies to projects hosted by The Apache Software Foundation (ASF).

Get to know GitHub

GitHub is the most popular platform for open source collaboration, so you’ll probably use it when exploring the world of OSS. First, you need to create a GitHub account and read the guide that helps you get started. On GitHub, you can contribute to projects by submitting issues and contributing code. Submitting issues means sending messages about errors in applications and suggesting ways to fix them. Contributing code involves sending pull requests with your corrections and improvements.

How did I find the drive and motivation to contribute?


I enjoy writing articles, and after I finished writing about habits and things I wish I knew earlier as a developer.Key habits and things I wish I knew earlier as a developerA listing of key habits and skills that could help you become a better

I thought to myself, an article on open source contribution would be amazing but, I had no track record of open source contribution.

Writing an article and sharing my knowledge was the motivation and drive for me to get started with open source contributions.

So far, my article on medium has reached over ~120K views and ~25K reads.

Here are some of the advantages of contributing to open source

  • Knowledge sharing
  • Increase your circle of influence
  • Build and promote your brand
  • Collaborate and communicate through code reviews and discussions
  • Give back to the community. ❤
  • Connect with like-minded people, find your next employee/employer, co-founder, mentor or mentee
  • Financial support
  • Increase the odds of future employments
  • Inspire and get inspired

Java Design Patterns

Design patterns are among the most useful practices for a programmer. They help you speed up the programming process by solving general problems much quicker. Design patterns provide you with tested development paradigms, so the development process becomes quick and straightforward.

You can reuse design patterns to avoid small errors and issues, leading to significant problems in your project. Another advantage of design patterns is they enhance your code’s readability for others. 

As the name suggests, Java design patterns is a collection of design patterns for Java. A product of seasoned architects and programmers, the patterns help you simplify development with Java. The project requires you to be familiar with the numerous Software Design Principles.

All the patterns in this project have useful descriptions to understand where you should use a particular pattern and where you shouldn’t. We recommend learning more about this project as it’s a must-have for every Java programmer. It has over 62 thousand stars on GitHub, so you can understand how popular it is. 

Finding projects to work on

One way to find projects to work on is to look to open source software you use often and like. Is there a tool, package, framework, or a language that you work with regularly and enjoy using? Find out whether it’s an open source project by checking its license and if it accepts contributions and is active. Working on things you already use gives you an edge when contributing because you’re already pretty familiar with how it works and have experience using it. As a bonus, you can address problems that have been bothering you or suggest features that you want in the software. If you are going to contribute code to the project, be sure you can work in the language it’s written in. 

If the above approach may not work for you, try using the Github explore page to find projects that are accepting contributions or actively want help. Github suggests projects you may like based on people and repositories you follow, star, and watch. Another way to find projects is to use Github’s search tool by entering beginner-friendly contribution tags like good-first-issuegood-first-bugbeginner-friendlyeasylow-hanging-fruitfirst-timers-only, etc. Filter search results to return issues in open states and in the languages you’d like to work in. There are tons of other tools, platforms, and programs where you could find open source projects that I’ll list at the end of this article to help you with your search. 

To have a positive contribution experience, try to avoid communities that are hostile to beginners and generally problematic. If for example, when trying to ask legitimate questions after you’ve done your research, you receive dismissive and combative comments or insults, it’s best to stay away. Another sign to be watchful for is a pattern of unprofessional behavior within a community. Some open source software projects have been infamous for this sort of thing. So do your research before contributing.  


If you’re interested in the Internet of Things (IoT), then you must get acquainted with Arduino. It is an open-source electronics platform based on simple software and hardware. An Arduino board can read various inputs such as a finger pressing a button, a tweet, or a light on a sensor and convert it into an output, such as turning on a torch, activating a system, or publishing something. 

As a microcontroller platform, it’s very accessible and easy to use. It has cross-platform compatibility as it can run on Mac OSX, Windows, and Linux. Even though it is quite simple to use, its versatility and flexibility make it suitable for experienced programmers.

If you want to use Java in IoT, then learning about Arduino would surely be a significant step. Its GitHub repository has more than ten thousand stars, so you can understand how popular it is.


Blynk is a prominent Internet of Things solution that allows to build web and mobile applications for the Internet of Things. You can use this platform to connect more than 400 hardware models such as ESP8266, Raspberry Pi, Arduino, and Raspberry Pi with drag and drop IoT mobile apps within a few minutes.

Blynk lets you connect your devices to design apps, the cloud, and analyze telemetry data. It is undoubtedly among the most prominent Java open source projects. If you’re interested in learning about IoT, then you should definitely start with Blynk. It is fast and provides you with proper connection management. Apart from those advantages, it allows you to connect with public and private servers. Its primary server is based on Java, so you can learn a lot from it.

Understanding how a project works

Not all open source projects operate in the same way. Some allow contributions from anyone. Some require you to work your way up to get contribution privileges. Some have multiple people involved in managing a project. Others have a single person in charge, a so-called benevolent dictator for life. 

Contribution guidelines help you understand how to approach your participation in a project. It will explain how to reach out about a contribution, provide templates for communicating bugs and suggesting features, list work that is needed by maintainers, project goals, etc. An amazing example is the Angular contribution guide which lists all kinds of useful information for new contributors like their commit message guidelines, coding rules, submission guidelines, etc. in great detail. 

In addition to contribution guidelines, some projects will have a code of conduct. It usually outlines community rules and behavior expectations. It’s meant to help you know how to be a amiable and professional contributor and community member. Angular, for instance, has an awesome code of conduct that lists what they consider unprofessional conduct, their responsibilities to the community, and how to get in contact in case someone violates it.   

Big projects may have governance policy and team documents that outline specific roles in the community, teams, sub-committees, contribution workflows, how discussions are conducted, and who gets to commit. These kinds of documents are essential to understanding how the community operates. The about page on, for example, lists who all the core team members are, their roles, and other contributors. On Github, they also have a docs folder containing policies regarding contribution.  

Even after you’ve gone through the documentation, you may still need to ask questions to active members of the community. Despite doing your research, you may still be stumped on a particular aspect of the project. To interact with other contributors, join community communication tools like Slack, IRC etc., sign up for newsletters, and subscribe to their mailing list. Angular uses Gitter as its community communication tool and directs contributors with questions/problems to Stack Overflow, where they can get help using the angular tag. Connect with community members and develop relationships with them as it will expose you to facets of the project that you may be unaware of. 

Having a good grasp of the technical aspects of the project and how it’s organized is essential to making contributions that meet the project’s standards. To understand technical parts of the project, consult the project README, wikis, tutorials, and documentation. Angular, for example, has docs explaining their Github process, building and testing, their coding standards, debugging, PR reviews, etc. Going a step further, look at past feature integrations and bug fixes in merged pull requests which are full of discussions by other contributors and can be a rich source of context. As the project evolves, pay attention to it, frequently follow issues, features, discussions, pull requests, and bug fixes to continually learn how it works. For instance, a contributor can follow this example of an Angular feature request discussion about a form API to better understand how Angular forms work, bundle size management, etc.

An open source project is sort of like a project at any company you might work at; there will be a house coding style, team culture, and workflows for getting things done. The difference is that open source projects can and will have a much different group of people working on them. 


This is a step by step guide to help you to start contributing to Open Source in Java. This article is primarily intended for people who are relatively new to open source and/or not familiar with the Java ecosystem.


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