introduce
Simply put, all the above names refer to one thing Java Platform, Enterprise Edition
The above nouns are shorthand for the following:
- J2EE(Java 2 Platform, Enterprise Edition)
- Java EE (Java Platform, Enterprise Edition)
- Jakarta EE(Jakarta Enterprise Edition)
The above sorting is sorted according to time evolution.
Why is it called J2EE
In December 1998, SUN released JDK1.2 and began to use Java 2this name.
In the second year, Sun, together with IBM, Oracle, BEA and other large enterprise application system developers, formulated an enterprise application system development specification based on Java component technology. The name is naturally called J2EE for short Java 2 Platform Enterprise Edition.
At the beginning, Sun hoped that this standard and Java-based extensions would be used by enterprise users.
According to the definition of Java version, Java does not use major version, so the number 2 is used naturally.
This leads to J2EE is really difficult to understand.
The most depressing EJB is the content in J2EE, because programmers are really upset about the container management and injection of this EJB, so there is a lightweight framework Spring, which is another evolution path.
The language specification for version 1.0 of Java is also now available at Berkeley's website: The Java Language Specification
Later, in the 1.2 version released in 1999, some extensions were split from the Java 1.0 version, and these splits were used by Sun to release the Enterprise Edition of Java.
For the content of the split-out enterprise part, a new name is needed, so the name naturally uses Java 2 Platform Enterprise Edition, the standard link: Java 2 Platform, Enterprise Edition (J2EE) Overview
This name has been in use since 2006.
Java EE
In 2006, the Java 1.5 version was released, and the name J2EE was discontinued. Indeed, the name is also difficult to understand.
J2EE was changed to Java EE or Java Platform Enterprise Edition
This name is simpler and clearer, and the more ambiguous number 2 is removed.
Jakarta EE
The time came to 2017, when Java already belonged to Oracle.
Oracle donated Java EE to the Eclipse Foundation.
According to Oracle's urgency, generally leave some points, the word "Java", Oracle will definitely not give it, and Eclipse has no way to use the word "Java" after getting Java EE.
What to do, change the name, Eclipse changed Java to Jakarta after a community vote.
This change is repeated with Apache's Jakarta, which is actually good, anyway, it finally has a name.
That's what's now called Jakarta EE for the part about Java Enterprise Edition.
The table below shows the Jakarta EE version evolution history.
in conclusion
In a word, the above pile of things are the packages in Java EE (Java Enterprise Edition) that most of them may not be used.