owasp foundation, the open source foundation for application security on the main website for the owasp foundation. owasp is a nonprofit foundation that works to improve the security of software.

github is where over 100 million developers shape the future of software, together. contribute to the open source community, manage your git repositories, review code like a pro, track bugs and features, power your ci/cd and devops workflows, and secure code before you commit it.

stack overflow is the largest, most trusted online community for developers to learn, share​ ​their programming ​knowledge, and build their careers.

in-depth, to-the-point tutorials on java, spring, spring boot, security, and rest.

a computer science portal for geeks. it contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview questions.

snyk helps software-driven businesses develop fast and stay secure. continuously find and fix vulnerabilities for npm, maven, nuget, rubygems, pypi and more.

well organized and easy to understand web building tutorials with lots of examples of how to use html, css, javascript, sql, python, php, bootstrap, java, xml and more.

bitbucket cloud is a git-based code and ci/cd tool optimized for teams using jira.