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 ...

learn more… | top users | synonyms

3
votes
1answer
3k views

Installing multiple versions of sun java

I have a need to maintain different versions of a certain product written in java, and uses sun's jdk to build. Some older versions of the product need an older jdk (1.5) and the newer ones need jdk ...
3
votes
2answers
1k views

Running J2ME (Java Micro Edition) Applications

What's the easiest way to run J2ME (Java phone apps) on Ubuntu?
3
votes
1answer
752 views

Tomcat and Eclipse Integration Error : “Unknown version of Tomcat was specified.”

I am using Ubuntu 13.10 and gnome 3.10. I have followed this tutorial Set up Eclipse and Tomcat 7 on Ubuntu 12.10 to create Java RESTful Web Services with Jersey to setup tomcat and eclipse. but ...
3
votes
1answer
4k views

Java memory usage ballooning to all RAM when running Minecraft Server

When I run Minecraft server, over time (a few hours to a few days) the memory usage by Java balloons to take up all available computer memory and the server performance then degrades: lags, players ...
3
votes
1answer
5k views

how to run java program in ubuntu in following situtations

sachin@sachin-Lenovo-G550:~$ java -version java version “1.7.0_21″ OpenJDK Runtime Environment (IcedTea 2.3.9) (7u21-2.3.9-1ubuntu1) OpenJDK Server VM (build 23.7-b01, mixed mode) When I ran the ...
3
votes
3answers
9k views

icedtea-7-plugin non-functional in Ubuntu 13.04

I installed(sudo apt-get install) icedtea-7-plugin (and all its dependencies) and have closed firefox and reopened it; and the plugin still does not appear in http//about:plugins Is there a fix for ...
3
votes
2answers
163 views

Ubuntu with Java Error

I have Oracle Java installed on my computer. Latest version 1.7 and path variables set properly. But most applications in Ubuntu from Software Center that require Java needs Open JDK Iced Tea etc. I ...
3
votes
1answer
554 views

Install JUnit with Oracle Java 7 already instaled

I am running Ubuntu 12.10 with Oracle Java 7 installed (as described here). I want to install JUnit 4 but if I do a simple sudo apt-get install junit, it starts to download openjdk and the like (which ...
3
votes
3answers
8k views

install red5 server on an ubuntu12.04 server

I've been struggling with this during 2 weeks without get it done. I'm building a website where the users will have to record a video and post it as there cv and for this I need a RTMP server. I ...
3
votes
4answers
2k views

Netbeans shows only blank window

I am not able to launch Netbeans. When I launch it for the first time I normally get the netbeans splash screen, but after that nothing happens. When I try to launch it again, a small blank window ...
3
votes
1answer
485 views

Poor Audio in Blackboard Collaborate (Elluminate Live) on Ubuntu 11.10

I already have Sun Java (not OpenJDK) installed, but I'm still having audio issues. OpenJDK didn't display the slides, which was fixed by Sun Java, but the audio was bad in both of them. Is there any ...
3
votes
1answer
10k views

First time using Java Web Start in Ubuntu - Fatal Launch Exception

I've been using Ubuntu for a while and Java Web Start applications have never "just worked" in the current or any prior version, so I ignored them until now. However, now I have a need to get them ...
3
votes
4answers
3k views

How do I remove OpenJDK?

I had removed OpenJDK installed by default from Ubuntu Software Center. Eclipse had been showing that Installed JRE is OpenJDK. I wanted eclipse should be configured to jdk I already installed and ...
3
votes
2answers
2k views

How to install Eclipse J2EE IDE from a tarball?

I have downloaded Eclipse 3.6.1 as a tar.gz file from eclipse site. Then I extract using cmd: tar -zxvf eclipse-jee-helios-SR1-linux-gtk.tar.gz after execute this cmd I got eclipse folder in this ...
3
votes
2answers
523 views

Packaging a Java web application: Reuse tomcat6 or separate process?

I would like to package my java web application http://kunagi.org/ for Ubuntu (and Debian). Should the package create a user kunagi, provide an init script and configuration files for the existing ...
3
votes
1answer
856 views

Why can't I play mp3 files in java

I am making a study guide in java to help me learn Japanese, but I have been having a hard time getting it to speak Japanese to me. Espeak did not work, so I used this code to get a .mp3 file and ...
3
votes
2answers
4k views

Unable to understand what jdk location is

I have java installed correctly for sure. aaa@ubuntu:~$ whereis java java: /usr/bin/java /usr/bin/X11/java /usr/local/java /usr/share/java aaa@ubuntu:~$ whereis javac javac: /usr/bin/javac ...
3
votes
1answer
136 views

Java installation failed

I am using Ubuntu 11.10 on flash memory due to corrupted hard drive that could hardly keep OS. Usually when computer get down because of empty battery or other reason it is reinstalled, the Ubuntu on ...
3
votes
1answer
1k views

Trouble installing Matlab due to java.lang.NoClassDefFoundError

So whenever I try to install Matlab, the first image appears, but then goes away and that's the end of it. Here's what I'm doing- user@host$> cd ~/mathworks_downloads user@host$> unzip ...
3
votes
1answer
1k views

Cannot install JDK 7

i have already extracted the files in the tar.gz files i also tried the sudo update-alternatives but it only says it doest have too since i already have one jdk and then when i try java -version it ...
3
votes
2answers
285 views

I can't find or run downloaded Geogebra

I can't find it. I can't run it. I have no idea what to do now that it's on my computer. I'm new at this stuff.
3
votes
1answer
531 views

Ubuntu 12.04 version of Netbeans doesn't have the JavaFX plugin

I just want to know why does Netbeans 7.0.1 from the official Ubuntu 12.04 doesn't have all the plugins (in especial the JavaFX plugin) on it while the official Netbeans from the website (even the ...
3
votes
1answer
709 views

How can I remove an unfinished java installation installed via terminal?

Well, since I was so stupid to install the java via terminal with official package, it stuck on the licence agreement screen, because I had to accept it, but no key from my keyboard worked to accept. ...
3
votes
2answers
496 views

Installing mods on Minecraft 1.0 does not work for Mo' Creatures

In attempting to get the Mo' Creatures mod working on Kubuntu 11.10 with OpenJRE-6 I get the following error: # # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) ...
3
votes
1answer
119 views

CUPS Print Delays [closed]

I am a developer of an open source Java printing plugin for the web browser and we have a client that reports 250ms delay in printing on Ubuntu, but no other OS. He has tested printing on Windows and ...
3
votes
2answers
264 views

Battery Indicator Missing, Cannot Install Because No JDK 7

I'm really new to the whole linux deal, but I'm on a laptop and a battery gauge would be extremely helpful. Whenever I try sudo apt-get install indicator-power it gives me: `Reading package ...
3
votes
0answers
161 views

How do I control the vmem when forking, as I'm getting different results on 10.04 lts and 12.04 lts?

Expected behavior (Ubuntu 10.04 LTS): mike@boontoo10:~$ java -version java version "1.6.0_45" Java(TM) SE Runtime Environment (build 1.6.0_45-b06) Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, ...
3
votes
1answer
74 views

How can I find out how often a program has started in Ubuntu?

How can I find how often a program (like firefox, teeworlds, thunderbird, etc.) has launched? I'm a Java programmer, so solutions that must be implemented programmatically are acceptable, and ...
3
votes
4answers
6k views

How to set the default Java version

I have been using Java 6 on Ubuntu 11.10, but now I want to update to version 7. I've installed version 7 via PPA as described here. If I run sudo update-alternatives --config java I get the ...
3
votes
0answers
532 views

Webex crashing/lockup Firefox / Chromium Browsers - Ubuntu 12.10 [closed]

When launching webex from firefox or chromium browser. Browser freezes and stops responding. Browser process must be killed to exit. Please help me troubleshoot this. Here are my setup details and ...
3
votes
2answers
3k views

How to set Value of JAVA_HOME variable

My /etc/profile code is: # /etc/profile: system-wide .profile file for the Bourne shell (sh(1)) # and Bourne compatible shells (bash(1), ksh(1), ash(1), ...). if [ "$PS1" ]; then if [ "$BASH" ] ...
3
votes
2answers
527 views

how to enable in chrome icedtea7 java plugin instead of icedtea6?

My chrome browser in ubuntu 12.04 uses iced6 plugin. Test http://java.com/en/download/testjava.jsp shows java6, but via update-alternatives I switched java/javac to using openjdk-java7
3
votes
1answer
1k views

Java 1.7 update 07 and Google Chrome

I've just updated Java from 1.6 to 1.7 via the Software Centre - removing the old Java 1.6 and selecting the new Java 1.7. Firefox works fine. But when I use Google Chrome to access a Java test ...
3
votes
0answers
116 views

How to do a ppa for a java ant project?

I was doing a launchpad ppa for my ant project using jdeb. when I had the unpleasant surprise in the last step that ubuntu ppa actually builds the package from the repository, not just accepts signed ...
3
votes
0answers
72 views

Unity sometimes can't seem to re-show a java GUI app (jpasswords) [closed]

I use a password manager called jpasswords because I can run it on most platforms and it can be self contained on a usb drive. Under Unity in Ubuntu 12.04, using openjdk, it runs fine, but if it get's ...
3
votes
0answers
913 views

How to compile and run Java file using Geany [closed]

I am trying to to compile and run .java file using Geany but its not working. Can anyone explain me why? Sorry for english.
3
votes
0answers
10k views

How to properly set up Sun's JDK? [duplicate]

Possible Duplicate: How do I install Oracle's JDK 6? I'm trying to manually install the Sun JDK package (I have my reasons, don't bother asking why). I've successfully extracted the ...
2
votes
1answer
1k views

OpenJDK - Oracle is better? [closed]

From http://www.wikihow.com/Install-Oracle-Java-on-Ubuntu-Linux Type/Copy/Paste: java -version . If you're having OpenJDK Runtime Environment (IcedTea6 1.10pre) (7b15~pre1-0lucid1) OpenJDK 64-Bit ...
2
votes
2answers
9k views

permission denied: /etc/apt/sources.list

I'm trying to install java jre, i usually do it like this sudo echo 'deb http://www.duinsoft.nl/pkg debs all' >> /etc/apt/sources.list sudo apt-key adv --keyserver keys.gnupg.net --recv-keys ...
2
votes
7answers
9k views

Matlab install - Java permission denied

Matlab version 2012. I know there are many threads about this, suggesting to chmod +x the following files (if you are in installation directory): sys/java/jre/glnx86/jre/bin/java ...
2
votes
4answers
15k views

Netbeans 7.0.1 installed but won't run

I installed Netbeans 7.0.1, and I've made sure to install all the JDKs and JREs I could find. It installed without errors. I also saw this question and made sure I followed all the instructions there ...
2
votes
4answers
373 views

How to start and kill the procedure?

I have some runnable-jar files. I want to run them at regular intervals and also kill those processes after some time. I am a newbie when it comes to Ubuntu or linux in general. Can anybody suggest me ...
2
votes
4answers
6k views

How can I get sikuli-ide to work?

I installed sikuli-ide with sudo apt-get install sikuli-ide Everything was fine until I tried to start it from the terminal. I typed sikuli-ide But the only response I got was [info] locale: ...
2
votes
2answers
3k views

How can I select which Java to use?

I have installed both OpenJDK 6 and 7. When I run "java somefile" from the command line, OpenJDK 6 is invoked. I do not want to change this default behavior. What command can I use to run my ...
2
votes
2answers
11k views

How to install/use JUnit?

I have installed JUnit on my Ubuntu 11.04 sudo apt-get install junit Then created a test file like: import org.junit.*; public class TestBasicLinkedList { @Test public void testCanAdd(String[] ...
2
votes
3answers
1k views

“cannot create directory `JAVA': Permission denied ” how to solve this issue?

can anybody help me in solving this issue. I am new to Linux and here's problem: gourab@gourab-RV509:/usr/share/java$ cd / gourab@gourab-RV509:/$ cd usr gourab@gourab-RV509:/usr$ mkdir JAVA mkdir: ...
2
votes
1answer
1k views

Java no longer works after upgrading to 12.04

I'm trying to run a .jar file on my computer. It worked in version 11.10, but in 12.04 now, I get a fatal error message from Iced Tea Web, saying it cannot parse the JNLP file. I've tried installing ...
2
votes
3answers
1k views

Where are Java JDK Sources?

I installed Java JDK but where can I find the sources? For one my homework, I'm asked to refer to one of the files ... check the source code of java.util.LinkedList. The Java source code of ...
2
votes
2answers
4k views

JAVA blocked due to security level on Ubuntu 13.10

JAVA being blocked because of security level. However, I am aunable to alter security levels in Ubuntu. I have dated to the latest JAVA: sudo add-apt-repository ppa:webupd8team/java sudo apt-get ...
2
votes
1answer
2k views

Cannot start Webex session. Java permission issue?

My fingers got ahead of me today and I managed to disable Java for Webex on my machine. (Install details: Ubuntu 12.04 32bit, Chrome 32.0.1700.77, Java v7, update 51, Webex working fine for a year ...