Issue
Me has been fighting with internet for a while for that single answer. Everything else now seems standing on it's place after this trip.
When I ask "What's Java SE" they say "Java SE is set of core Java classes ...... platform ... develop desktop apps .... contains core libraries and APIs ..... Java EE is a spec set to be implemented ...... Java EE is built on top of the Java EE". Sometimes they mention javac and JVM, sometimes they don't. What they do never (almost) is mention JDK.
When I ask "What's JDK" they say "JDK is set of stuff that lets us build apps on Java including javac, JVM etc." and never (almost) mention Java SE.
When I ask "Difference between Java SE and JDK" they give me that page and nothing more to think about. What does this mean: "Java SE product name for JDK"? Can't clearly understang right now.
Lack of terminology presicion and experiece for me? Possibly yes. I think would be able to answer this question myself if I were more experienced.
The questions:
- "Whether (Java SE) == (JDK) or not?" (pls with wide explanation and terminology clarifications when needed).
- Is Java SE a spec set like Java EE or not?
- Can I find precise definitions somewhere to look at?
Sorry for a big writing. It proves that I would really love to put an end to this.
Solution
“Java SE” is three things:
- An abbreviation of “Java Standard Edition”
- A trademark owned by Oracle Corp.
- A set of specifications published by Oracle Corp.
Anybody in the world is free to write software that implements the Java SE specifications. In the past, several companies have done so.
However, anybody in the world is not free to use the trademark of Java. To use that trademark, a person or company is required to come to terms with Oracle in a licensing deal. Presumably that deal would require payment.
Long story short, and over-simplified for brevity… Some of the companies that previously wrote their own implementations of Java SE decided to join forces, combine their codebases, and publish the whole thing as open-source. These companies included Oracle, IBM, and Apple. Thus was born the OpenJDK project (Wikipedia). Since then, other companies and individuals have joined the project.
The OpenJDK name is a trademark owned by Oracle. However, Oracle has published permission allowing others to use the term with no payment required.
The OpenJDK project published source code to an implementation of the Java SE specifications. The project does not publish built binaries or installers.
Several vendors do publish built binaries or installers for implementations of the Java SE specs. Nearly all of these implementations rely largely, if not entirely, in the OpenJDK source code.
These binaries/installers vendors include, in no particular order:
… and more.
Most of those built binary or installers products use OpenJDK in their name or in their descriptions, as allowed by Oracle. A few of those products may use the term Java or Java SE with explicit permission from Oracle.
There are other editions of Java technology:
- Java Card (for smart cards, badges, etc.)
- Java ME, or Micro Edition (for constrained devices)
- Java EE, or Enterprise Edition (a wide collection of specifications that run on top of an implementation of the Java SE specs, aimed at developers making software for enterprise oriented users)
The first two, Java Card & Java ME are owned by Oracle. The third, Java EE, was donated by Oracle Corp to the Eclipse Foundation were it is now known as Jakarta EE. Jakarta EE is a collection of specifications, with various vendors publishing implementations.
The term “JDK” refers to Java Development Kit. This kit includes an implementation of the Java SE specs, plus tools to write Java apps. These tools include a compiler.
The term “JRE” refers to Java Runtime Environment. This is a JDK minus some of the software development tools.
The term “JVM” refers to Java Virtual Machine. A JVM is a piece of software that enables a Java-based app to execute at runtime on a particular kind of host computer and operating system. Java apps are platform-agnostic, in other words, are not “native”. So a Java app needs a particular JVM to know how to run on a Mac, on a PC, or on a mainframe.
Every JDK and every JRE contains a JVM.
Answered By - Basil Bourque
Answer Checked By - Katrina (JavaFixing Volunteer)
