How to install JDK 11 under Ubuntu?

Setting the primary JDK

When juggling various JDK versions, set OpenJDK 11 as the default:

• Choose your Java warrior:

sudo update-alternatives --config java

• Don't neglect the Java compiler:

sudo update-alternatives --config javac

To view the entire line-up of your JDKs:

update-java-alternatives --list

Leveraging SDKMAN! for JDK management

Turn to SDKMAN! to manage multiple Software Development Kits in parallel on Unix systems:

• Bring SDKMAN into play:

curl -s "https://get.sdkman.io" | bash

• Ready SDKMAN for action:

source "$HOME/.sdkman/bin/sdkman-init.sh"

• Let SDKMAN fetch the Java version you want:

sdk install java 11.0.3-zulu

• Check what your new miniboss can do:

sdk version

Adding new repositories for fresh JDK versions

To get your hands on the latest JDK versions, consider adding new repositories:

• Add the OpenJDK PPA:

sudo add-apt-repository ppa:openjdk-r/ppa

• Eagerly fetch the new package details:

sudo apt update

Laying out JAVA_HOME environment variable

Need to launch some applications? The JAVA_HOME environment variable is here to help. Specify the home for your JDK by adding to your .bashrc:

• Get ready for some coding:

nano ~/.bashrc

• Declare your new home:

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64

• Time to put this into action:

source ~/.bashrc

Sorting out potential pitfalls

Encountering installation hiccups? Here’s what might be the culprit:

• Antique versions: (Buh-bye! 👋 sudo apt remove older JDK versions.)
• Shoddy network: Good old "Have you tried turning it off and on again?"
• Permission snags: When your system cries "Sudo, who?", you know what to do!

Balancing multiple JDKs

For power users, wielding different JDK versions might be necessary. Here's why:

• Development: Even software has its own model catwalk.
• Stability: Can't let the stable geniuses down!
• Exploration: Like unchartered waters, but for coders.

Remember, with great power (to switch JDKs), comes great responsibility (to know which version to use).