Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, Java Expression Language and WebSocket technologies.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Java is a class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible.
Liferay is an open-source company that provides free documentation and paid professional service to users of its software.