We've all had that feeling before. We see something happening in front of us, yet because the sight doesn't conform to the worldview held within our brain, we just can't believe our own eyes. Dogs playing poker. Cats wearing panty hose. Politicians telling the truth. You get the idea. And depending on your personal threshold for incredulity, you might experience this feeling as a double take, a spit take or a psychotic break. If you happen to be prone to psychotic episodes, then I'm going to have to ask you to move on. Wait for tomorrow's WTF. Or maybe pet some kittens. Here's a picture to help you get started.

Feeling calm and relaxed? Good. Now let me tell you a story about Steve. Steve is what you call a 'skeptic' (which is scarily close to septic, but I digress). He questions absolutely everything he encounters. He walks with overly firm footfalls to make sure that the ground won't open up under him. He carries two watches to act as verification for the clock on his smartphone. He even checks his own pulse to make sure he's alive.

What's worse is that Steve carries this tendency into his job as a developer. He writes if statements with a true block, a false block and an else block. And when comparing strings? The equality operator just won't cut it. Consider the following code.

``````public static void setDelay(String delay) {
String yes = "YES";
if ((delay.hashCode()) == yes.hashCode()) Scenario.delay= 10000;
}
``````

Passing a string as a parameter instead of a Boolean is something that, possibly, could be forgiven. But when it comes to checking for the value of the string, Steve is way too skeptical to just use an equal sign (or two). Instead, the hash code for both incoming value and the test value are generated and compared. Because, as everybody knows, the equality operator is not trustworthy for strings, but has no problem when comparing long integers.

Ironically (and not in the Alanis Morisette sense), by using the hashCode method, Steve has actually changed a simple comparison that was pretty certain to be accurate into one that actually could fail. After all, hashCode is not guaranteed to be unique for each string (that is, a perfect hash). So out there, somewhere, may be another string whose hashCode value actually matches the hashCode for "YES". And there are hackers working hard to find unanticipated ways to delay the scenario.

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