Jakarta EE is a set of specifications: an open-source platform that offers a collection of software components and APIs (Application Programming Interface) for the development of enterprise applications and services in Java. During these last years, Jakarta EE has become one of the preferred frameworks for professional software enterprise applications and services development in Java.
There are probably dozens of such open-source APIs nowadays, but what makes Jakarta EE unique is the fact that all these specifications are issued from a process originally called JCP (Java Community Process), currently called EFSP (Eclipse Foundation Specification Process). These specifications, initially called JSR (Java Specifications Request) and now called simply Eclipse specifications, are issued from a consortium, bringing together the most important organizations in today's Java software development field, originally led by the JCP and now stewarded by the Eclipse Foundation.