Pretty much every single bug or WTF in our legacy web app is the result of mis-managing or abusing mutable state. I am absolutely convinced that mutation is the

Pretty much every single bug or WTF in our legacy web app is the result of mis-managing or abusing mutable state. I am absolutely convinced that mutation is the enemy of reliable software. This is a good writeup, but I think we need to do more to demonstrate the difference to the average Java-slinging code monkey out there.