software installation
After issuing apt-cache search jdk, I see both openjdk-8-jdk and openjdk-9-jdk listed. I am unsure which one I should install.
I took a look at SDK downloads from Oracle's website below, and I wasn't able to immediately find SDK 9. Why would this be the case?
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
Unfortunately Java Web Start is no longer included since Java 11 SE. Excerpt from Java Client Road Map (Update 2018-03-05):
Java Web Start has become a migration path for developers as browser vendors continued to restrict plugin support over the past several years.
Since it is predominantly a desktop technology,Web Start has some limitations. In particular, it requires a standalone JRE to be installed and maintained on the user’s desktop.
However, over the past decade,vendors of the most popular desktop operating systems have emphatically pushed for applications on their platforms to be delivered bundled with integrated, sandboxed runtimes. Increasingly they require desktop applications to be distributed through their own private "app stores".
The notion of an application being distributed separately from a standalone JRE is,therefore,quickly fading.
Consequently:
Oracle will extend support for Web Start in Java SE 8 from March, 2019, through at least March 2025.
Oracle products that have dependencies on Web Start will remain on Java SE 8 and continue with the support timelines as indicated by those products.
Oracle will not include Java Web Start in Java SE 11(18.9LTS)and later.
Oracle will begin encouraging application developers and users to transition away from Java Web Start and encourage non-commercial consumers to remove any unused or non-supported Oracle JRE installations from their desktops.
Developers who deploy desktop applications to individual consumers (eg, games, personal banking, or other B2C applications) will need to transition to other deployment technologies such as the jlink and/or third party packaging and deployment solutions before the end of 2020.
Application developers who target applications for internal data processing, business, commercial, or production purposes, will either need to seek commercial license with Oracle, or transition to other deployment technologies by January 2019.
Therefore, if you really need Java Web Start you need to switch to Java 8.
Go here to get to the download page.
Note the new licensing agreement...
Go to the bottom of the page, find the area shown below, accept the license agreement, click the download link...
Once downloaded, double-click on the .deb file to install it.
Best Answer
If you are planning to install NetBeans then install openjdk-8-jdk because openjdk-9-jdk is not compatible with NetBeans from the default Ubuntu repositories, at least it is not compatible with NetBeans in Ubuntu 16.04. The version of NetBeans in 16.04 is NetBeans 8 which targets Java 8 as its compatible Java version. NetBeans from the default Ubuntu 18.04 and later repositories, is compatible with openjdk-11-jdk.
Another alternative is to install both openjdk-8-jdk and openjdk-9-jdk and use either
update-alternatives(which is installed by default in Ubuntu) orupdate-java-alternatives(which is installed when openjdk-8-jdk is installed) to manually choose which Java to use before running an application. See update-java-alternatives vs update-alternatives --config java.