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Java

There have been great changes to Java in the last year. Java 11 is the current ``long term support'' version and ALMA now uses this when building its Java-based software tools. Unfortunately, Java 11 doesn't include the previously standard installation method (Web Start) and so this is no longer available. A new installer based on InstallAnywhere has been developed that should continue to offer a more user-friendly and automatic installation to that offered by the ``tarball'' approach.

For Cycle 8, a version of Java will be distributed together with the new installer and thus it should no longer be necessary to have Java 11 installed on your machine. However, a tarball download without Java will also be made available and, if so, the situation is unchanged from before i.e. a fully functioning Java Runtime Environment (JRE) must be installed and only Java 11 will work correctly.

However, Cycle-7 observing will continue during the Cycle-8 Call for Proposals and thus many users (especially observatory staff) will continue to need access to both OT versions during most of 2020. Therefore, we recommend that versions of the Cycle-8 OT which contain a JRE are downloaded and that Java 8 remains the main system-wide installation for use with the Cycle-7 OT.

Whatever version of Java is installed, its version number can be checked by typing java -version on the command line, the output of which should look something like this:

java version "1.8.0_271"
Java(TM) SE Runtime Environment (build 1.8.0_271-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.271-b09, mixed mode)
The number that follows the underscore refers to the update of the Java version that has been installed. When reporting a problem with the OT, the full version number including the update should be reported.

It may be possible to work with two different user-installed versions of Java (i.e. 8 and 11) and switching between these.


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The ALMA OT Team, 2021 Feb 03