Installing Java on a Flash Drive

Question

I'm really tired of computers not having the necessary Java version I need, or I don't have admin privileges to install it. I've seen tons of windows tutorials, but I'm on a Mac. So can someone tell me how to put Java 7/8 on a flash drive, and how to create a script to run a jar file with the version on my drive I have selected? Thanks! I'm on Mac OS X 10.10

Answer 1

Based on your comment to another answer

I have a computer I can do it on with admin privileges

It sounds like you just want to have the JVM/JDK on some portable media that you can run from after you plug it into another computer. This should be simple assuming you only plan on using it on comparable systems. For example, you won't reliably (or at all) be able to install Mac x64 java binaries on a flash drive and try to run it on a Windows machine.

So assuming you only intend to run it on comparable machines, it's as simple as copying the directory structure from the root of the Java install directory. On my Mac OsX 10.9.5 it's /Library/Java/Home. Once you have it on the drive, you just plug it into another Mac. It should automount and you open up a terminal to the root of that mount. cd into the $JAVACOPY/bin (where $JAVACOPY is the directory structure you copied) and you can run ./java -version to verify you are running it.

If all is well after doing that, you can launch any JAR file from that flash drive mount directory with

  cd /Volumes/flashMount/Java/Home/;
  ./bin/java -jar /Users/myuserid/myJar.jar 

Keep in mind that Java doesn't strictly require any of the formal install process that systems like Mac and Windows surround it with. All of the fluff involved with "installing" java is about setting up the system to use whichever Java version is installed without the user having to know or care. But you can have as many versions of java as you want in the file system without "installing" them and they should all function just fine (ignoring classpath collisions for certain libraries.)