Can someone help me with an issue? I want to do TopCoder﻿. It needs a Java applet. I'm new to ubuntu, have the 13.04 version and have no idea how to get Java installed and which version of it should I get for the applet? Please suggest what to do. Thanks in advance.
14447
How do I install Java, including in my browser, so websites with Java work?
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When I try to run a simple Hello World program I keep getting a message saying Could not find the main class.   I found  which suggested that my CLASSPATH variable is messed up, but I couldn't find a way to fix it.  What am I doing wrong?
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If I have a Java source file (*.java) or a class file (*.class), how can I convert it to a .exe file?  I also need an installer for my program.
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I only recently discovered the different JVM's on the  page and thought I'd start tinkering. Its been difficult to find documentation on how to configure Java on Ubuntu though.  Lets say I wanted to change the JRE or JDK that I'm using, I could crack open a terminal and say  sudo update-alternatives --config java   And then pick from one of the installed versions.  If I'm understanding JVM's right (which I may very well be not), You can configure the openJDK to use alternative JVM's (Eg JAMVM) and run it as such  jamvm -jar foo.jar   2 questions,  1: Do i have the concept of a JVM right? As in, is this possible?  2: If so how do i configure the JVM and switch the default to a JVM of my choosing?
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While looking to compile OpenJDK from source, the newest General Availability version () insists on OpenJDK 9 or 10.  JDK 11, however, is not due to be released until .    However, to my surprise, when I do apt search openjdk the result is:  ... openjdk-11-jdk - OpenJDK Development Kit (JDK) ... openjdk-8-jdk - OpenJDK Development Kit (JDK) ...   No OpenJDK 9 or 10!  And wait, is that OpenJDK 11?  Maybe a Beta release?  Nooo....  So I looked at apt show openjdk-11-jdk:  Package: openjdk-11-jdk Version: 10.0.1+10-3ubuntu1 ...   Why has OpenJDK 10 been packaged as openjdk-11-*??
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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 above command this showed that Java is installed in my system, but when I am going to compile any Java program it gives the following error message:  sachin@sachin-Lenovo-G550:~/programs$ javac abc.java The program ‘javac’ can be found in the following packages: * default-jdk * ecj * gcj-4.6-jdk * gcj-4.7-jdk * openjdk-7-jdk * openjdk-6-jdk Try: sudo apt-get install   Please tell me how to get rid of it and run my Java program.
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I know very little about how Java works and its interactions with OS X, so I'm partly looking for an expert and simple description on how Java works on the Mac, and why so much press includes "fear, uncertainty, doubt" but no concrete details about how and why Java is not safe..  I want to use the Bitcoin client , but to do so I will need to install Java which over the past six months I've only heard bad things about.   So my question is: How safe is it for me to install Java on Mac OS X 10.8.3?   (The hidden question inside this question is what version / source of Java I should select if I can depend on Apple to keep Java secure.)  I understand "safeness" is a fairly difficult thing to define, but just some general advice would be greatly appreciated. Even if someone could point me in the direction of some learning materials so I can work this out for myself, that would be great.
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I want to create an Ubuntu desktop app, specifically to replace Gwibber.  I can code in Java, Python and a few other technologies. Adobe Flex would have been an option until Adobe decided to suck some more and stopped support for AIR on Linux.  Note - I don't care about supporting other OS's. It will be a personal Ubuntu specific app. It can I open-source, I don't mind extra help.  It should integrate seamlessly with Ubuntu, notifications and all.  I guess Python it is, is that correct? How do I get started?
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First, thank you in advance for any help that you can give a recent transplant from Windows to Ubuntu. I have a question that I have been seeking the answer too but I draw a blank at every turn.  I design websites, free of charge, for nonprofit organizations that are just starting and do not have the resources to hire a design firm. I am in need of a flash/swf editor and compiler. I had a program that I used with the awful previous O/S, however WINE would not run the program.   Thank you in advance for any help that you can offer. Since I do not earn a dime for doing this, I would prefer if the program was open source, however any suggestions are greatly appreciated.
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On Ubuntu 12.04 LTS I have installed Sun's JDK7, Eclipse, and the Arduino IDE. I want the Arduino to use OpenJDK 6 and want Eclipse to use Sun's JDK 7.   From my understanding I need to manually choose which Java to use before running each application. This led me to the update-java-alternatives -l command. When I run this I only see the following:   java-1.6.0-openjdk-amd64 1061 /usr/lib/jvm/java-1.6.0-openjdk-amd64   but when I run update-alternatives --config java I see the following:   *0  /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   auto mode 1  /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   manual mode 2  /usr/lib/jvm/jdk1.7.0/bin/java                   manual mode 3  /usr/lib/jvm/jre1.7.0/bin/java                   manual mode   I don't understand why the update-java-alternatives doesn't display the same 3 options. I also don't understand how to switch between OpenJDK6 and JDK7. How I can go about using the OpenJDK6 for Arduino development and Sun JDK7 for Eclipse/Android development?
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I'm a C++ developer - not a java developer, but have to get this code working...  I have 2 public classes that will be used by another product.  I used the package directive in each of the java files.    package com.company.thing;  class MyClass ...   When I try to compile a test app that uses that I add   import com.company.thing.*;   The javac compiler fails with errors about com.company does not exist.  (even if I compile it in the same directory as the class files I just made a package of)  I am sure I am doing something bone-headed and silly.  I've read the  pages and tried to set up a directory structure like /com/company/thing  etc, but either I have totally screwed it all up or am missing something else.  EDIT thanks for the suggestions - I had tried the classpath previously.  It does not help.  I tried compiling   javac -classpath &lt;parent&gt; client.java    and the result is:  package com.company does not exist   I have the code I want to import (the two java files) in \com\company\product.  I compile those fine.  (they contain MyClass) I even made a jar file for them.  I copied the jar file up to the parent directory.  I then did (in the parent directory with the client java file)   javac -cp &lt;jarfile&gt; *.java   the result is:  cannot access MyClass bad class file: MyClass.class(:MyClass.class) class file contains wrong class: com.company.product.MyClass Please remove or make sure it appears in the correct subdirectory of the classpath.   EDIT  I got the client code to compile and run if I used the fully qualified name for MyClass and compiled it in the parent directory.  I am totally confused now.    compiled with no classpath set - just   javac *.java    in the parent directory - and it worked fine.  I can get a test app to compile, but that is not going to cut it when i have to integrate it into the production code.  Still looking for help.  EDIT:  Finally - not sure why it didn't work before - but I cleaned up all the files all over the directory structure and now it works.    Thanks
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I want to install Oracle's JRE and to update to the latest version with the Software Updater when they released. Is there a Ubuntu package that is provided by Canonical or Oracle?  Before release Java 7, I followed  to install Java 6.  But it doesn't work for Java 7. There is no package sun-java7-xxx. How can you install Java 7?
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I already installed Java 8, but I don't know how to install Java 7 and how to switch between the two Java versions.   I also want to switch between Java 7 and 8 to update a project I am working on. I am a new Ubuntu user, so be very specific.  added: 12/31/2017  gero@4790k:~$  lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 16.04.3 LTS Release:        16.04 Codename:       xenial   When I try to use:  gero@4790k:~$ sudo apt-get install openjdk-7-jdk Reading package lists... Done Building dependency tree Reading state information... Done Package openjdk-7-jdk is a virtual package provided by:   oracle-java9-installer 9.0.1-1~webupd8~0   oracle-java8-installer 8u151-1~webupd8~0   oracle-java7-installer 7u80+7u60arm-0~webupd8~1 You should explicitly select one to install.  E: Package 'openjdk-7-jdk' has no installation candidate   I don't even know how to select the the java installer 7u80.  Or if you can tell me how to install jdk-7u80-linux-x64.tar.gz or jdk-7u80-linux-x64.rpm .
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I am trying install Oracle Java 8 on Ubuntu 18.04 LTS.  $ java --version  Command 'java' not found, but can be installed with:  sudo apt install default-jre             sudo apt install openjdk-11-jre-headless sudo apt install openjdk-8-jre-headless     According  i added ppa:  sudo add-apt-repository ppa:webupd8team/java   and after that i updated my os:  $ sudo torsocks apt-get update Hit:1 http://ppa.launchpad.net/webupd8team/java/ubuntu bionic InRelease         Ign:2 http://dl.google.com/linux/chrome/deb stable InRelease                    Hit:3 http://us.archive.ubuntu.com/ubuntu bionic InRelease                Hit:4 http://dl.google.com/linux/chrome/deb stable Release               Hit:6 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease       Hit:7 http://us.archive.ubuntu.com/ubuntu bionic-backports InRelease Hit:8 http://us.archive.ubuntu.com/ubuntu bionic-security InRelease Reading package lists... Done   and then I ran:  sudo apt-get install oracle-java8-installer   But I got :  $ sudo torsocks apt-get install oracle-java8-installer Reading package lists... Done Building dependency tree        Reading state information... Done Package oracle-java8-installer is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'oracle-java8-installer' has no installation candidate   I found this  but it is not working and I got same error
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If I don't want to install a GUI, just install a minimal Ubuntu amd64.  Ok, but: I heard that I can still run e.g.: Firefox in a "framebuffer" (?), so I'm asking, that how can I run e.g.: a VLC media player through a framebuffer under console, without "GUI"?
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I used NetBeans for Java development on Windows and remember finding it in the Ubuntu Software Center on Natty, but now it's gone. Is there a PPA I can use or will it be re-added to the official repos?
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Is there a GUI IDE for programming python just like java has netbeans?  I wanted one where we could drag &amp; drop test boxes &amp; labels just as we do in swing components using netbeans or eclipse.  Or is there an add-on present in either netbeans or eclipse itself?