Managing Java Files on your Linux VPS & Troubleshooting Java Print

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Many people often have issues using Java applications within a Linux environement.
To keep plans affordable, most hosting companies will offer Linux operating systems instead of Windows.

This is because:

  • Linux often performs better, has lower requirements
  • Linux is free (versus thousands of dollars for Windows server licensing) so it keeps costs low for customers
  • Linux can pretty much do everything a Windows machine can, with more support and flexibility

However, you may run into some "issues" using Java on Linux. We'll be addressing the issues on Ubuntu 14 w/ LXDE, which is what we use for our servers.

I need a different version of Java

  • Our VPS plans meant for use with Java usually have two versions installed: Oracle Java 6 and Oracle Java 8
    One is for backwards compatibility and the other is for newer applications. The default is set to Java 6, but programs open in Java 8 by default.
  • Sometimes your program will require a different Java version, or you may prefer a different version
    You will need PuTTY. Once downloaded, enter your server's IP, click 'Open' and enter root as your username, then paste your password.
  • There are different versions of Java:
    • Oracle Java
      To install Oracle Java, you need to do a manual install. However, there's a guide here that might help. 
    • OpenJDK
      Installing OpenJDK is easy. Just type in apt-get update and then once it's updated type in apt-get install openjdk-7-jre to install version 7
      You can look up the repository package name for other versions you require
  • Please note that you may still need to update the default by using the command update-alternatives --config java and then selecting version
  • The version of Ubuntu we use is meant to be lightweight. This has it's disadvantages. If you change your Java version, you have to open the .jar via terminal
    • To open via terminal, go to your start menu and find XTerm which is your terminal application
    • Type in java -jar jarname.jar where jarname.jar is the file's name, after going to the directory where the Java file is located
    • For example, to go to the desktop directory on your desktop, type in cd /root/Desktop/

Downloading a new Jar file

  • If you need to download a new Jar file that is not included on your server, just use Mozilla and download it
  • Move it to the proper folder and use the cd command to go to the directory, as described above
  • Type in chmod a+x jarname.jar where jarname.jar is the file's name. This will mark your Java file as executable, so you may now open it.

Program opens but crashes

  • Please run the Java file from Terminal by typing java -jar <filename>.jar
  • Review the info and make a support ticket

We've hope that's helped. If you're not already a customer, we recommend becoming one, as we can assist you further if this tutorial did not help resolve your issue.

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