Category Archives: Code fun

Java 4-ever

I find this video hilarious…

You should use the best tools at hand to solve the problem. That said; choosing between Java or .Net doesn’t really matter in most cases. There are however some areas where Java is a better choice and vice versa.

I can’t wait to see it in the cinema 🙂

PS. I do develop with Java even though I do not blog much about it.

Update: YouTube removed the video due to copyright claims. You can still see it JavaZone.

Monitors and thread context

Running the below code will fail – why?


var syncRoot = new object();

Monitor.Enter(syncRoot);

ThreadPool.QueueUserWorkItem(x => Monitor.Exit(syncRoot));

It will throw a SynchronizationLockException with the message “Object synchronization method was called from an unsynchronized block of code.”

It is because System.Threading.Monitor requires the Enter and Exit methods must be executed on the same thread for the same synchronization object.

I did not know that :-/

When is DivideByZeroException thrown?

What a strange question most developers will say. DivideByZeroException
is thrown every time you divide by zero, right? No – it depends.

Let’s try – regular division with integers.

int i1 = 4;
int i2 = 0;

try
{
Console.WriteLine(i1 / i2);

}
catch (System.DivideByZeroException)
{
Console.WriteLine("DivideByZeroException");
}

Hmm, I see a DivideByZeroException coming, and that’s
absolutely correct. So what is all the fuzz about?

Let’s try again, but this time with floating point numbers.

double d1 = 4.0;
double d2 = 0.0;

try
{
Console.WriteLine(d1 / d2);

}
catch (System.DivideByZeroException)
{
Console.WriteLine("DivideByZeroException");
}

If you try to run this piece of code, no exception is
thrown. Instead INF (short for infinite) is returned. To be more precise a PositiveInfinity,
due to the decimalNumerator is positive.

I read this somewhere and had to test it. I even asked
my colleagues when DivideByZeroException is thrown and showed them these code examples.
None of them knew the right answer. So it’s not only me, whom is ignorant. 🙂