10,000 Foot Developer

The title is the remainder for evaluating the numerical sequence 9876543210 as an Integer in Java.  This number lies outsides the bounds of Integer.MAX_VALUE for Java; it’s an overflow error.

1286608618 is the overflow remainder for casting 9876543210 as an Integer in Java.

I ran across this error in some code I was working on that had credit card type account numbers; which are generally 16 digit numbers.  The program in question got the *same* account number from one table as a string, another database as an Integer, and a third table as a BigDecimal.  In the code there were also methods that did conversions  of this number to long and to int.  Normally values like this are stored as strings but I have no comment about the design of this software and database where such things could occur . . .

When the value 1286608618 came back as a value during a unit test, I thought it odd and instead of just taking it as incorrect I researched it.  Since a lot of people use 9876543210 as a test value, perhaps a lot of people have seen this.

There are a few interesting things about this error:

1. Java doesn’t complain when the bad number gets assigned to Integer.
2. Java just mindlessly returns the overflow value with no error.
3. Java makes a few trips through its Integer range until it gets a number that fits within the range.  In the case of 9876543210, it is over 2 times the value of the range, to Java makes those trips through to get to 1286608618.

I wrote a little Groovy code to play around with this:

//Here's the integer and it's overflow
Integer i = 9876543210
println "overflow error for 9876543210: " + i

//Integer max value
BigInteger maxInt = 2**31 - 1
println "calculated max integer: \t" + maxInt
println "Integer.MAX_VALUE: \t\t" + Integer.MAX_VALUE

//Integer min value
BigInteger minInt = -2**31
println "calculated min integer: \t" + minInt
println "Integer.MIN_VALUE: \t\t" + Integer.MIN_VALUE

//get the Integer range
BigInteger range = maxInt  + 1 - minInt
println "range: \t\t\t" + range

//two trips around the raspberry bush calculation
BigInteger big = 9876543210
println "big: \t\t\t" + big
println "overflow remainder: \t\t" + (big - (2*range))

Here’s the outcome:

Well see here, I know thinking about this bakes my bean a little bit too.  There are number shifts and all kinds of thing going on. If you have underflow the same kind of logic applies as well.

I don’t understand why it just doesn’t error — what use is that remainder number at all?  Have no idea.

Firefox.  Dang it.

Coding some javascript and waiting for a build, I was checking out my OK Cupid profile and wiped my Chick-Fil-A grease on my LA Clippers t-shirt when someone walked up and said –

“OMG!!!  You are using Firefox!  What a moral outrage!”

Crap.  Can’t win here.  Time for a new third browser.   I have to use IE (reality) and Chrome.  IE, sigh.  Good ideas, bad implementation like a Corvair.  Oops that’s non-PC too.  Wait were Corvairs bad cars? Can’t remember.

Believe it or not I work in the stone ages and can’t install Safari on my Win 7 machine.   You need admin rights for that.  I know, crazy – a developer without admin rights????; my setup starts with what the front desk has which is so nuts.  But . . . I CAN install Opera.  And Opera is kinda neat because it’s a *version* of Google Chrome and is also my mobile browser of choice.

For a long time I didn’t do this because I couldn’t install any good plugins but this has changed – Opera 20 has a plugin that let’s you install Chrome plugins.

The two I absolutely need (besides developer’s stuff):

• Xmarks — very implement for sharing project links between browsers, especially during testing.  And the profiles are awesome.  I organinze my research in folders this way too.
• Controlled Multi-tab Browsing — this lets me limit my browsers to 9 tabs.  I am an infernal tab opener, and I read at Lifehacker.com that all’s you need are 9 tabs max — and I’m following that right now.  And seriously it’s a big help.

Be careful about the multitab limit plugins.  There’s another Chrome one I cannot recommend called Tabalot that does this (explicitly from their plugin site):

After reaching a configurable open tab limit (that excludes pinned tabs) Tabalot will automatically close the left-hand non-active tab.

There’s no prompt or anything as of this date – just closes the darn tab.  Sounded great until it closed a Google Doc I keep open all day and I lost my information for the day.

—

So anyway in Opera you can install Chrome plugins.  It’s a big deal to *me* because XMarks doesn’t have a deployment for Opera. To do this you need to first install a plugin called Chrome Extension.  Here are the steps:

• Install Opera’s Chrome Extension.
• Install your favorite Chrome Plugins – Opera will be treated like Chrome because they are based on the same WebKit core – as is Safari.
• Xmarks will work properly in Opera (or it has for me in version 20).  Joy of Joys.

Now when these politics and religion talking people come sauntering around they’ll just see me with Opera, Chrome and IE.

But did I uninstall Firefox?  Heck no.  Never know when it might be PC again and Chrome be the next offender. I’m even keeping Sea Monkey on my PortableApps just in case someone sees me shopping at Walmart or the Co-op and complains about my browser.

I guess there’s always wget.

Like many, I use Xmarks plugins to manage my bookmarks across multiple web browsers.

Recently the Xmarks install on Chrome was breaking.   I sync anything and got a 503 error.

After spending some time looking into it and finding no answer on the Xmarks site or anywhere else, I decided to reinstall the plugin, which resulted in a successful fix.

Here are the steps:

• Backup your Chrome bookmarks:  ctrl-shift-O (or use the tool menu) to open the Bookmark Manager –Then Organize–>Export Bookmarks to HTML file. If you don’t backup you could make a mistake during the Xmarks sync and lose everything.
• Uninstall the Chrome Xmarks Extensions from Chromes Customize Menu–>Settings–>Extensions.
• Reinstall the Xmarks Extension.
• Sync up XMarks.  If you use profiles, you can cancel out of the initial sync wizard, and then go into the Options in Chrome and assign the profile.
• During the sync wizard I chose this setting which kept it from destroying my bookmarks on my other browsers and in Chrome:

• Tonight is the first of the hands-on developer meetings – Ale and Algorithms – for our EC Tech Meetup at the Milwaukee Burger joint in Eau Claire.  7 pm.  Tonight I’m hoping to work on some problems including
  
  • Fizz Buzz
  • Armstrong Numbers
  • Prime Number detector
  • Reverse a String without API use
• Since the meeting is only an hour or so long we may not get through all these.  I’ll be using  Groovy  . . . and beer and cheese curds.
• This is the first of hands-on meetings to do TDD, build build servers, open source VM, and solutions for private business.
• How exactly can you do TDD whne you are using Acceptance Tests as a target?  So . . .in (say) a two week iteration you start off with broken tests and then fix them?  The build server then reports red for two weeks. Yikes.  And imagine a release of several iterations over a few months . . . maybe thats an insane target and TDD doesn’t work on that level.
• After you release an iteration MAKE SURE the business experts review the AT criteria and outcomes.  All that may have changed by the end of development.
• In DB Unit — if you are loading your data from an XML file make SURE the first record of the same table has ALL the fields even if it doesn’t use them!  Else you’ll get a “Broked” error — can’t load missing fields.  For instance:

This breaks:

   <Object  Date=”[some_date]” ID=”77″  />

   <Object  Date=”[some_date]” ID=”77″  ObjectNumber=”3751″/>

This doesn’t:

   <Object  Date=”[some_date]” ID=”77″  ObjectNumber=”3751″/>

   <Object  Date=”[some_date]” ID=”77″  />

• Java’s Big Decimal: Again, to iterate: instantiating with a STRING is better than a DECIMAL — but you just have to live with the non-compile time check. Sigh.  But don’t want those nasty decimals hanging off.  Here’s a pic of a Groovy test (compiles to Java):

Pretty important in financial calculations.  More on this later sometime.