Now that I have read all the responses in this thread (thank you!) and done some more digging of my own, here are a few more insights I have picked up as a Java-outsider / newbie:
- The current release of Java Standard Edition (SE) is 15; but many applications are still using version 8 or something in between.
- The enterprise version (EE) of Java is now called Jakarta and part of the Eclipse foundation [0] Focus on Cloud Native (Kubernetes, Docker ...)
- naming schemes: Java 1.8 is just Java 8, Java 1.11 is Java 11 etc.
- the versioning cadence of Java has changed with version 10 (in 2018) from "every few years" to "twice a year", that's how we got to version 15 in such a short period of time.
- The officially recommend way to build Android apps today is in Kotlin, but there is still support for Java.
- The JDK is used for developing apps in Java, the JRE just to run those apps. The two seem to be converging: everybody just downloads the JDK. The JDK contains a debugger, a shell, a document generator a compiler etc.
- OpenJDK: the project containing the Java source, is available in two builds OpenJDK and OracleJDK (the difference seems to be in commercial support from Oracle, not in code / functionality). Oracle is the primary contributor to OpenJDK [1][2]
- The current release of Java Standard Edition (SE) is 15; but many applications are still using version 8 or something in between.
- The enterprise version (EE) of Java is now called Jakarta and part of the Eclipse foundation [0] Focus on Cloud Native (Kubernetes, Docker ...)
- naming schemes: Java 1.8 is just Java 8, Java 1.11 is Java 11 etc.
- the versioning cadence of Java has changed with version 10 (in 2018) from "every few years" to "twice a year", that's how we got to version 15 in such a short period of time.
- The officially recommend way to build Android apps today is in Kotlin, but there is still support for Java.
- The JDK is used for developing apps in Java, the JRE just to run those apps. The two seem to be converging: everybody just downloads the JDK. The JDK contains a debugger, a shell, a document generator a compiler etc.
- OpenJDK: the project containing the Java source, is available in two builds OpenJDK and OracleJDK (the difference seems to be in commercial support from Oracle, not in code / functionality). Oracle is the primary contributor to OpenJDK [1][2]
[0] https://jakarta.ee/
[1] https://www.marcobehler.com/guides/a-guide-to-java-versions-...
[2] https://openjdk.java.net/faq/