“But little Mouse, you are not alone, In proving foresight may be vain: The best laid schemes of mice and men Go often awry, And leave us nothing but grief and pain, For promised joy!”
From “To a Mouse” (translated), by Robert Burns
As Burns so nicely stated, it was a great plan. Still is, actually, just not for October 12th! The inaugural Thanks for Sharing Informal International HackFest will be rescheduled for a later date – sometime in November, in all likelihood – due to a last-minute assignment on a short-suspense Java EE project. When duty calls…
Anyway, please check back (or keep your eye on my Twitter feed @MkHeck) for updates. Looking forward to a good time with great friends soon, creating & seeing some fun & useful projects. Until then!
Do you love programming in Java (or for the JVM)? Learning new things? Do you enjoy just hanging with friends and exploring new ground, sharing in discoveries small and large? If so, consider yourself invited to the first, uh, periodic Thanks For Sharing Informal International HackFest, a virtual event scheduled for October 12-13, 2013!
The Genesis
Some of us were chatting on Twitter about how fun it would be to get together and just jam at the keyboard. So I thought, why not? Yes, that’s all there is to it. Good doesn’t necessarily have to be complex. 🙂
The Idea
First of all, this isn’t a conference; it’s a hackfest, up to 24 hours of friends and soon-to-be friends around the world just hanging out and banging out code for fun. No pressure to “bring your A game”…in fact, the central theme of this particular gathering is to pick out something you’ve been planning to explore and just haven’t had the chance yet. BYOP: Bring Your Own Project! Want to know more about CSS? RESTful Web Services? Cryptography? Java SE or ME on the Raspberry Pi? Whether you want to explore JavaFX custom controls or lambdas, OpenJDK or Jetty, pick something and plan to pound away at it…all in great company.
This isn’t an official event sponsored by Oracle or anyone else; it’s just a gathering of like-minded developers. Chat a lot, say nothing at all, stay an hour or all 24. It’s up to you!
Ground “Rules”
Well first, there aren’t any. Nothing hard and fast, anyway.
But here are some suggestions, if I may:
Sometime before October 12th, think of an idea, something fun you can work on for a few hours and gain something from the experience.
Log into the Google Hangout whenever you can – it’s okay, we’ll be there 24 hours!
Explore, chat, ask questions, offer helpful advice…be as social as you’d like! Or not. Quiet is fine, too. 🙂
It would be really nice of you to post any useful code you come up with to GitHub. No pressure, don’t feel you have to do…but even code you consider very rough or “exploratory” may be helpful to someone else. And the more we all share, the more we all learn!
That’s it, really. Just a bunch of folks getting together to tinker with code and hang out. What are you waiting for?!?
The Details
Oh yes, the details! Here they are:
Begins: 1200 (noon) UTC/GMT on Saturday, October 12th
Ends: 1200 (noon) UTC/GMT on Sunday, October 13th
Where: Google Hangouts
Calendar reminder and invite will be sent to all who want to join in the fun.
RSVP
This is your part! If you’re interested in participating, drop me a line by clicking this link. And please share, repost, and retweet to others who might like to be a part. Come on, it’ll be fun! Join us for the first Informal, International HackFest…and Thanks For Sharing. 😀
Renewable energy (RE) has long been a passion of mine, but practically speaking, it simply hasn’t been cost-effective to implement at a personal level. Factoring in credits, location, type of RE, etc. can often tip the scale, but generally speaking, an investment in RE would require more commitment than simply “running the numbers.” No judgment here, I understand and appreciate both sides of that argument.
In recent years, though, things have changed. Not entirely, and not across the board even now…but with inexpensive (yet quality) RE equipment being produced in the US, China, and many locations throughout Europe, one can begin to experiment with RE on a much smaller scale and determine if/how it makes sense for your particular situation.
As a software engineer, I also work to integrate whatever I build into a more manageable, usable system. Physical computing promises many things, which I’ll coarsely lump into the term “better living” – but to do it right requires more than just assembling some hardware. The intersection of devices with software and the greater internet results in what is often termed the “Internet of Things”, or the IoT…and this is where the potential for “better living” can skyrocket, if things are properly integrated. It’s a small and limited example, but how much more useful is a fully-integrated system that is easily managed from anywhere on the planet than a complex system composed of numerous components…all of which must be monitored individually and manually?
For this post, we’ll focus solely upon one small portion of that integrated system: adding PV, or photovoltaic (solar) panels to a functioning small-scale RE system. Before these additions, the system consisted of:
Wind turbine
Deep-cycle battery bank
Arduino to control sensors, radio transceiver
Temp/humidity and current/voltage sensors
Radio transceiver, primarily for comm link to send readings
Now we’re adding a solar charge controller and initially, two 25W solar panels wired in parallel for a total of 50W maximum.
In future posts, I hope to elaborate on the software side because (as stated above) that is where the difference truly lies. For now, here are some pictures (and a very short video) of the PV addition:
Connecting the PV Panel
Mounting the PV Panels to the Backing Board
Initial Two Panels Mounted
Simple Wire Terminals on PV Board
Charge Controller Mounted, Not Yet Connected
Charge Controller Mounted AND Connected! The “Sun” light indicates power from the panels; the “Battery” light flashes while charging attached batteries.
And finally, a short video to give a glimpse of the PV portion of the system in action:
In future posts, I plan to provide more information about the “good stuff” (teaser: JavaFX, Java Embedded Suite, more Arduino, BeagleBone Black, wireless management, and more!), but a system must exist before it can be monitored and managed. As we continue to “build out” the system, those opportunities will only increase. Stay tuned, and please feel free to comment below or drop me a line. Thanks for visiting!
I’ve been working recently with a client to do some rather useful things with notifications, and one of them involved sending a secure email from within a Java program. We encountered some interesting (translation: weird!) challenges, and in overcoming them, I worked out a reasonably straightforward path through the minefield. If you’ve been thinking about secure-email-enabling your Java app but aren’t sure where to start, hopefully this will serve as a fairly quick and mostly painless primer. 🙂
The Problem
Let me first say that if you only want to send a plain-text email from Java, there are ways to do that without much fuss and without any external players. If you want to sign or encrypt your emails, though, you’ll need a couple of extra components:
A digital certificate (private/public key pair issued by a recognized Certificate Authority, or “CA”)
A means of using the certificate to sign and/or encrypt the email
The goal is to digitally sign an email to assure recipients that the sender of the mail is indeed me (or you, if you’re following along at work/home). Let’s get started!
Getting Your Tools in Order
Getting a Certificate
First, we have to have a digital certificate. If you already have one, you can skip this step…but if not, StartSSL offers free user/email certificates for personal use. Just point your browser to the StartSSL site and click the large button labeled “Sign-up”. You’ll need to provide them some information, enter the verification code they email to the address you provide, and they do the rest…including installing your new cert and the certificate chain into your web browser.
Freeing the Certificate from your Browser
Perhaps the easiest way to use a certificate is to store it (keys, certificate chain) in a Java Keystore (jks). Extracting your shiny new certificate from your browser is a relatively easy (albeit drawn-out) process. From your browser, export your certificate, including private key. This will produce a .pfx file, which is a PKCS12 keystore. From Chrome, you simply:
Click on the Wrench (or Lines) icon in the upper-right corner
Select “Settings” from the menu
“Show advanced settings…” at the bottom of the page
Scroll down to the section labeled “HTTPS/SSL”
Click the “Manage certificates…” button to display your certificates.
Then, from the certificates window:
Select the target certificate and click the “Export…” button
Click “Next” from the Export Wizard window
Choose “Yes, export the private key” and click “Next”
Under the “Personal Information Exchange – PKCS #12 (.PFX)” entry, select the options to “Include all certificates in the certification path if possible” and “Export all extended properties” (NOTE: Do NOT choose to “Delete the private key if the export is successful”. No no no!) and click “Next”
Enter a password (twice) and click “Next”
Provide a path/filename for the export and click “Next”, and finally…
Confirm the export options and click “Finish”.
Now that we’ve liberated your cert from the browser, let’s make it usable by our (non-browser) Java program.
Creating a Java Keystore
The fastest, easiest way I’ve found to convert a .pfx file to a .jks (Java Keystore) file is with the Oracle 11g database client. The database client can be downloaded by following this link, selecting the “See All” link to the right of your listed operating system, and choosing the 11g client from the OS-specific download page. Once it’s downloaded and installed, you’re ready to proceed.
Like the .pfx file, the Oracle wallet is a PKCS12 keystore, and the orapki utility (and other tools) included with the database client can be used to manipulate it…as long as it thinks it’s dealing with an Oracle wallet. To make that happen, simply rename the .pfx file to ewallet.p12. Since we aren’t dealing with the Oracle Wallet Manager, we don’t have to worry about meeting OWM’s password criteria or other niceties. Yes, that really is all there is to it!
Now, to make a Java Keystore. To do that, you’ll need to open a command prompt and do the following tasks:
Create an ORACLE_HOME environment variable that points to the install location of the Oracle client
Run the following command, pointing to the orapki utility under %ORACLE_HOME%\bin (in Windows) or $ORACLE_HOME/bin (Mac/Linux/UNIX):
You should now have a brand new Java KeyStore! You can verify its contents with the OpenSSL keytool utility:
keytool -list -keystore <java_key_store>
Now that we have our credentials in order, on to the Java side of things!
Building the Solution
There are several Java libraries available that aid in signing and/or encrypting email. Of the non-commercial options I found, all use the Bouncy Castle Crypto API and libraries as their underpinnings. Bouncy Castle (BC) may have a funny name, but it’s all business with regard to encryption.
At a very high level, you need to do the following things to create/send a signed email:
Provide the email “essentials”: SMTP server host & port, email addresses (sender & receiver), a subject, content, and the sending user’s password
Add BC as a new crypto provider
Retrieve the cert from your Java Keystore
Create and sign the email using the BC API/libraries
Send the email
There is much more you can do of course, but these are the “must-haves”.
In preparation for developing our secure email module, I created a proof of concept (BCCrypTool) by marrying a Java email program I’d written previously and some BC sample code…code reuse at its lowest level, but still good for the environment. 🙂 What you see here in my GitHub repo is a bit of streamlined Java code that should be pretty easy to repurpose. Please feel free to take a copy and do just that, and if you make significant changes/improvements and are able and inclined to share them, please feel free to do that as well. Sharing is caring. 🙂
A quick note on libraries. You’ll need the following to make this work:
