Develop Reference

How to install OpenJFX 11

I am trying to install the latest version of BlueJ, and it requires JDK 11 and OpenJFX. I have updated from Java 8 to 11 now, but I cannot find a way to actually install OpenJFX. I've tried to check the version of Open JFX, but I get an error message, and GDebi installer says that the dependancy is not there. No, sudo apt-get install openjfx is not working. Could anyone please help?
Output:
dpkg: dependency problems prevent configuration of bluej: bluej depends on openjfx (>= 11); however: Version of openjfx on system is 8u60-b27-4.

Looks like your openjfx is in older version, version for Java 8. You can either:
purge old installation and install openjfx-11,
download archive from openjfx website, extract it and link your projects to extracted directory.
Maybe there is an option to force installation of openjfx-11 but I prefer to purge old files first. Otherwise you may have a "little mess" later on.

IntelliJ Idea - Install JDK 1.8 on Mac

I use IntelliJ IDEA Ultimate 2017.3.3 and need to use Scala Version 2.12 for a project. However, IntelliJ says that JDK 1.8 is required for Scala Version 2.12. My problem is that I cannot select/choose JDK 1.8. Hence How can I set/install JDK to 1.8?
Any help is heavily appreciated.

Here you can download the Java JDK 1.8. After installing it, it should appear as an option inside IntelliJ.
UPDATE:
Find File -> Project structure menu and go to Project Settings -> Project tab. If on Project SDK the Java version 1.8 SDK is not selected, change it and click OK.

In 2022, you can use just brew
brew install openjdk#8
and then add into Intellij IDEA as new SDK with the following path:
/usr/local/opt/openjdk#8
maybe you need to update PATH env:
export PATH="/usr/local/opt/openjdk#8/bin:$PATH"
…and for the future give a try to sdkman, is better than brew
curl -s "https://get.sdkman.io" | bash
then open a new shell and try list to see what you could install ;-)
sdk list java
At time of writing you could use:
sdk install java 8.0.312-tem

2023 on Mac chip only brew install --cask adoptopenjdk8 and then use in terminal vim ~/.zshrc with export JAVAC_HOME=/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home/ inside that file.

installing JDK and it shows empty icon

When I tried to install the JDK, it was installed but in start->java Development Kit: I faced with "empty"word.
But when I went to cmd and writed javac version or java version I saw true results and when I tried to install SDK for programming android with eclipse or install android studio I had not any problem for installing
But after installing when I created a new project in both softwares I had problems.
What I must do? Every time I try to install JDK it is installed as now.

jenkins install fail in suse,java>=1.6 is needed

the environment is:
suse linux enterprise server 11 x86_64
jenkins-1.563-1.2.noarch
I have manually download and installed jdk 1.6.0_45 64bit,command "java -version" succeed show the jdk version.
but when i try to install jenkins,it shows:
error failed dependencies:
java >=1.6 is needed by jenkins-1.563-1.2.noarch
anyone can help to resolve it?

You either have to install the java package which comes with Suse, or (if that's not available) install Jenkins manually.

How to get javax.comm API?

I'd recently downloaded a project on SMS sending, but when I tries to compile the code it gives error on line import javax.comm.*;.
Can anybody tell me where to find javax.comm and where to place so that there will be no compilation error.

Oracle Java Communications API Reference - http://www.oracle.com/technetwork/java/index-jsp-141752.html
Official 3.0 Download (Solarix, Linux) - http://www.oracle.com/technetwork/java/javasebusiness/downloads/java-archive-downloads-misc-419423.html
Unofficial 2.0 Download (All): http://www.java2s.com/Code/Jar/c/Downloadcomm20jar.htm
Unofficial 2.0 Download (Windows installer) - http://kishor15389.blogspot.hk/2011/05/how-to-install-java-communications.html
In order to ensure there is no compilation error, place the file on your classpath when compiling (-cp command-line option, or check your IDE documentation).

Use RXTX.
On Debian install librxtx-java by typing:
sudo apt-get install librxtx-java
On Fedora or Enterprise Linux install rxtx by typing:
sudo yum install rxtx

you can find Java Communications API 2.0 in below link
http://www.java2s.com/Code/Jar/c/Downloadcomm20jar.htm

Another Simple way i found in Netbeans right click on your project>libraris click add jar/folder add your comm.jar and you done.
if you dont have comm.jar download it from >>> http://llk.media.mit.edu/projects/picdev/software/javaxcomm.zip

On ubuntu
sudo apt-get install librxtx-java then
add RXTX jars to the project which are in
usr/share/java