I’ve been thinking about setting up a Linux VM on my Mac for a little while now.  I already have a Chrome VM.   While I installed Java 7 on my Mac yesterday from Open JDK, I also wanted an “official” version.  In case I come across anything odd, I want a way to know if it is from the Mac version being not quite ready or “the way things work.”  Which gave me a reason/excuse to install the Linux VM.  This blog entry is about how to get started.

WARNING: Java 7 is not yet production ready.  See Java 7 Ships with Severe Bug.  (it has to do with loops not functioning properly and affects Lucene and likely other things.)

For the Mac

Download and install

1. Download Java 7 dmg file
2. Install it
3. Optional go to Java in system preferences to choose Java 7 as default.  (I did not do this since it sounds experimental with known buts at this point.)
4. Note the install location to reference is /Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home/bin.

Pointing to Java 7

alias javac7='/Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home/bin/javac'
alias java7='/Library/Java/JavaVirtualMachines/1.7.0.jdk/Contents/Home/bin/java'

To validate the aliases are working:

Jeanne-Boyarskys-MacBook-Pro:~ nyjeanne$ javac7 -version
javac 1.7.0-internal
Jeanne-Boyarskys-MacBook-Pro:~ nyjeanne$ java7 -version
openjdk version "1.7.0-internal"
OpenJDK Runtime Environment (build 1.7.0-internal-b00)
OpenJDK 64-Bit Server VM (build 21.0-b17, mixed mode)

Linux VM on VirtualBox

Download and install

1. Download ubutntu iso file.   It took a number of hours to download the iso file.  (I let it run overnight.)  While the download was less than 100MB, I downloaded Lion the night before (over 3GB) so my ISP may be throttling my connection speed now.  That or a slow server.  Note that you don’t need to create a USB stick or CD.  Just the iso file is fine.
2. Create a new VirtualBox VM and set CD drive to read from the downloaded iso file.  Even those these instructions are for Windows, they were easy to follow on a Mac.
3. Try to downloadthe .tar.gz file for Java 7.  I got a page not found so I tried the .rpm file.  This gave me errors when I installed and tried to run it.
    javac -version gave:
   Error occurred during initialization of VM.  java/lang/NoClassDefFoundError: java/lang/Object
4. Deleted the bad install.
5. Tried again to download the .tar.gz file for Java 7.  This time the path was found.

Pointing to Java 7

A really simple Java program

A really simple program using a Java 7 feature to further test your setup.

<pre>import java.util.*;

public class JeanneTest {
  public static void main(String... args) {
    System.out.println("test");
    Set<String> test = new HashSet<>();
  }
}