The GlassFish application server is the industry standard for Java EE. GlassFish 5 is the reference implementation for Java EE 8, so it contained more up-to-date features than any other Java application server available at time of Java EE 8 release. It is a fully featured and easy-to-manage application server, making it a powerful choice for deploying modern and robust Java EE applications. Although plenty of excellent application server choices are available, with many of them being Java EE 8 compliant or working in that direction, GlassFish will remain the best choice for those who want to utilize the most current implementations in the Java EE space since it is the reference implementation for the platform at the time of this writing. The downside to utilizing GlassFish is that there is currently no production support offered for the server, as it is open source and not a licensed vendor product.