One of the most important things that you need to know about Jakarta EE is that it is a standard, formerly managed by the Java Community Process (JCP) and now managed by the Eclipse Foundation.
A standard... for what? Well, for an application server! A Jakarta EE application server, for instance. This means that you can develop your Jakarta EE application knowing it will run in an environment that provides a bunch of resources that you can rely on. It also means you can easily move from one application server to another, as long as you stick to the Jakarta EE patterns instead of some vendor-specific feature (which is considered bad practice). Your application should have the same behavior no matter what Jakarta EE-compatible server you are using.
Beyond being a standard, Jakarta EE is also a certification. For a Jakarta EE server...
