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Originally posted by Ulf Dittmer: The difference is in whether you want to catch that you have mistakenly typed "=" instead of "==".
if (null = varName)
doesn't compile, while
if (varName = null)
That's true for C++, but not for Java. "null" is not a boolean expression in Java. Try it!
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
The correct way is not to use Java. The very existence of null itself is a language flaw. You can workaround its existence optimally by failing as early as possible upon its detection i.e. entry into contract implementations (concrete methods). This optimal approach works surprisingly well, but is only optimal within the context of Java. The correct approach, and moreso for a statically typed language, would have failure at compile-time (no such thing as null).