What are the pitfalls of a Java noob? [closed]

Question

I've gone through a few Java questions on SO. And I must say the content here is pretty well written and the Java guys on SO can really pump out the answers.

But what I always found was Java answers for Java people. Which is great on its own, but I'm a Java noob. So I don't really care for the workings of "Joint union in type parameter variance". It's probably handy down the line but for now.. it's not.

So Java for a noob (coming from PHP and Python) what are the cheatcodes?

If you could link to an SO answer (which is probably out there but I couldn't find) or write up what are the things Java does differently than other languages? (on a basic level)

Some might call these the Java Gotchas (I couldn't find the official one though)

Answer 1

There's a collection of semi-official "gotchas", known as the Java Puzzlers, and documented in a book of the same name; you might also find a few screencasts on the web. Periodically, Joshua Bloch and Neal Gafter like to present a bunch of innocuous-looking challenges and proceed to systematically remove any notion you had that you understood even the vaguest basics of the Java language.

On a slightly less cynical note, if you're looking to avoid many of the common design and implementation cock-ups, you might take a look at Effective Java, by the aforementioned Joshua Bloch, which has a wealth of decent advice on how to go about designing several of the important - but frequently badly written - aspects of writing components in Java, including a comprehensive explanation of how to properly implement the contract of equals() and hashCode(), and why you should avoid clone() like the plague.

Oh, and don't compare strings with the == operator.

Answer 2

Saying that objects are passed by reference.

Actually, methods work only with copies of object references..which are passed by value.

Java only works with pass by value.

Also worth reading: Is-java-pass-by-reference?