Questions tagged [java]
Java is a programming language originally developed by Sun Microsystems. Questions here should be about the installation, configuration and troubleshooting a JVM (Java Virtual Machine) or a JRE (Java Runtime Environment). Programming questions (unless directly related to Ubuntu) should be asked on StackOverflow.com.
3,232 questions
1
vote
0
answers
32
views
Thread switching timeout and zero CPU usage in Docker Java container after hibernate on Ubuntu 22.04 server
I deployed a Java service on Ubuntu 22.04 server using Docker. The service frequently switches threads during operation. I use systemctl hibernate to suspend the server, which allows for quick ...
- 11
0
votes
0
answers
78
views
Text and icons are too small in Java apps
I've struck a big flaw with Ubuntu. Well, Linux probably. I have a high resolution Acer Swift Go laptop. To be able to read the screen I have to either set display resolution to 1920x1080 at 125% ...
0
votes
0
answers
83
views
Why does the SNAP installation of JMol fail to load Calcium Lactate, but the direct Java command line works fine
I installed Ubuntu 25.04 and then installed Java :
$ java -version
openjdk version "21.0.8" 2025-07-15
OpenJDK Runtime Environment (build 21.0.8+9-Ubuntu-0ubuntu125.04.1)
OpenJDK 64-Bit ...
- 323
0
votes
0
answers
79
views
javaws.jar could not be located to start josm.jnlp
After some file cleaning to get Chromium running normally and not freezing the system, I can't run JOSM anymore. The josm.jnlp runs on Openwebstart. Openwebstart 1_12_0 starts but then gives a fatal ...
- 1
0
votes
0
answers
194
views
Updating SWT WebKit for Xowa (offline WIkipedia application) Error in 22.04 with possible Eclipse issue
I am getting an error when I try to start an application called Xowa (for offline Wikipedia). I do have Eclipse already installed but have never used it so I don't know the settings or anything like ...
0
votes
0
answers
43
views
Unable to start Battlescribe using Java
I use Ubuntu Mate 24.04.02 LTS.
Typing java -version, I get this:
openjdk version "21.0.7" 2025-04-15
OpenJDK Runtime Environment (build 21.0.7+6-Ubuntu-0ubuntu124.04)
OpenJDK 64-Bit Server ...
- 121
0
votes
0
answers
92
views
Davmail started with JRE 1.8 --add-exports error
When starting davmail (6.3.0-3627-1) on Ubuntu, I am getting the following info/error:
Using system provided JRE
openjdk version "1.8.0_452"
OpenJDK Runtime Environment (build 1.8.0_452-...
- 1
1
vote
0
answers
65
views
Minecraft 1.8.9 two upper rows of keyboard doesnt work
i am using Kubuntu 25.04, keyboard is Dark Project 87 fuji (site) cz and us layout, Minecraft is launched with Modrinth, Minecraft version is 1.8.9 and i am using laptop MSI Pulse AI 16 C1VFKG.
The ...
0
votes
0
answers
79
views
is there a way to configure Ubuntu to allow Java Robot to move the mouse?
In the old days, Java Robot had MouseMove, mouseClick, and text input that would allow one to interact with, say, a browser (opened and on top of your desktop) and drive it like a user would.
It (...
0
votes
0
answers
45
views
Trying to verify Java memory settings get applied in Apache Tomcat
We're running into heap issues for our web application. In trying to increase the JVM settings for the webapp and validate that they're taking effect, we're running into some confusing data.
We've ...
- 101
0
votes
1
answer
191
views
First time downloading OpenJDK on Ubuntu. Update Alternatives?
So, this is my first time using Linux, and I wanted to download OpenJDK for Java. When I ran sudo apt install openjdk-21-jdk-headless, i received messages on update dependencies. Here's one of them:
...
0
votes
0
answers
210
views
unable to install jre and jdk in ubuntu 24.04.2 [duplicate]
unable to install jre and jdk in ubuntu 24.04.2
number of tries:
ubuntu@ubuntu-VirtualBox:~$ java -version
Command 'java' not found, but can be installed with:
sudo apt install openjdk-17-jre-headless ...
- 1
0
votes
0
answers
91
views
Problem geting java working
My hardware: Dell Latitude 5310, 16gb ram, 256gb SSD,
Installation Ubuntu 25.04.
Need to install Oracle Java 8 to work with specific software that not work under open java.
Downloaded jdk-8u451-linux-...
0
votes
0
answers
48
views
JDK Upgrade Availability
I'm currently running Ubuntu 22.04 and using JDK version 21.0.6, which I installed via apt. However, my vulnerability scanning tool has flagged this version and recommends updating to JDK 21.0.7 or ...
0
votes
1
answer
96
views
No checkbox in Files to make a file executable
I'm new to Ubuntu (with a teeny bit of experience using Mint) and I'm experiencing a weird problem:
I think there is a terminal workaround but I would like to fix the issue in Files in case stuff ...
- 9