Detroit JUG Java 9 hacker group

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Matt Schuetze

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Mar 28, 2017, 3:21:27 PM3/28/17
to Sivakumar Mambakkam, Gerald Wiltse, Ravinder Jilkapally, fpa...@yahoo.com, John Pacuta, Mazin Al-Hamando, si...@altair.com, Mazin Al Hamando, matt_...@hotmail.com, micha...@gm.com, dearbo...@yahoo.com, anusha....@gmail.com, Roger S, i3detroi...@googlegroups.com
Hello everyone. I'm providing this email as a summary of our Saturday event.

The first ever Detroit JUG hackday occurred on Saturday, March 25. Six DJUG members with five students from Lawrence Tech University under guidance from DJUG member Professor Mazin Al Hamando, met at i3Detroit in Ferndale for a morning of software testing. Our objective was dissecting the Java SE 9 specification and exploring the corresponding Java 9 early access implementations from Oracle and Azul. We got through several exercises that helped our understanding of differences between the current Oracle JDK 8 footprint, and the various shapes of OpenJDK 9 deployments on Windows and Mac. Participants indicated the session was worthwhile and would indeed do such a session again in the future. We ended the day with a tour of the i3Detroit maker shop facility, learning how i3 members use all kinds of materials, machines, and tools to build really cool things. We are now inspired to focus on next hackday on home automation using Java, so we can start controlling the physical world through our software skills. Thanks to everyone who came out for the hackday and for i3 to host us!

I sent out the above summary on the DJUG Meetup today. Here were the exercises as transcribed from the white board:

Exercises:
In cmd shell/terminal, issue java -version
In cmd shell/terminal, set JAVA_HOME, and PATH=%JAVA_HOME%\bin;%PATH
In file explorer, find "java.exe"
Windows: 
    in cmd shell, set JAVA_HOME, which will be local to shell only.
    system wide, you can set JAVA_HOME in Environment Variables (rare for just testing a JDK)
Mac:   
    use jenv
Linux:
    use java alternatives
Launch Metalworks (or SwingSet2)
    [%JAVA_HOME%\bin\]java -jar metalworks.jar
Run jconsole, connect to Metalworks.
Inspect java.exe with Process Explorer from sysinternals.com (now part of Microsoft)

Now with pitfalls. I think Mazin should give this as an exam or quiz!

In cmd shell/terminal, issue java -version
    What is a command shell?
    Java.exe not found in path. Where is it?

In cmd shell/terminal, set JAVA_HOME, and PATH=%JAVA_HOME%\bin;%PATH
    Should JAVA_HOME include \bin?
    Is PATH search order first-found or last-found?

In file explorer, find "java.exe"
    It's in C:\ProgramData. I don't see that folder in File Explorer. Why not?

Windows: 
    in cmd shell, set JAVA_HOME, which will be local to shell only.
        I set JAVA_HOME in my command window, then shut it down. Why didn't it save?
    system wide, you can set JAVA_HOME in Environment Variables (rare for just testing a JDK)
        I just set JAVA_HOME system wide, but its still not set in the open command shell I had open. Why not?
Mac:   
    use jenv
Linux:
    use java alternatives

Launch Metalworks (or SwingSet2)
    [%JAVA_HOME%\bin\]java -jar metalworks.jar
        I know Metalworks is found in the JDK's demo\jfc folder. But there is no \demo folder anymore. Where to get it?

Run jconsole, connect to Metalworks.
       jConsole starts but cannot connect to the running Java process. What might be the problem?

Inspect java.exe with Process Explorer from sysinternals.com (now part of Microsoft)
    Oooooh that's cool! Where can I learn more about processes, environments, contexts, threads, etc.?

Also attached are the two photos I took.

Thanks again to i3 and especially Roger for hosting our session.

Matt




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