I just read an article on Slashdot about Compiled vs. Interpreted/JIT Compiled languages. It seems to suggest that Interpreted/JIT Compiled languages (mainly Java) run faster when written properly and are easier to port or don't need any porting.
1.) Is Java any easier than C++?
I was just wondering because if so that would significantly improve my development time because I have to compile for MacOS, Linux, Windows, DOS, etc. and on every platform I have to change stuff.
2.) What would be the disadvantages of using an Interpreted/JIT language?

It would have been wise for you to read the comments on Slashdot as well.
Boils down to this: Java is not C++ 2.0. What I mean by that is that it's a whole different tool, not something to replace C++ or any language for that matter. Same goes for Interpreted languages. They are not inheritly better than anything, they are just different.
So:
Use the right tool for the job

If you're interested in Java, study it. Learn for yourself the advantages and disadvantages. Because whether something is easier to use or not depends on the coder. I personally love coding in PHP, others don't. It has nothing to do with solid, conrete advantages or disadvantages. I just like PHP, and thus I code better and faster in it.

EDIT:

It's either the other way around or both. Native programs can run faster if written properly. Remember, Interpreted langauges when run through JIT end up as native code. So how could it ever possibly be faster than native code?
The reason why it seems to be faster is that sometimes the JIT'r can optimise the code on the fly. Such is the case with mathematical calculations, for example. But you could do the same in native code if you wanted.

For most games Java is fast enough. I'm sure it is possible to code Far Cry or Quake4 in it without losing too much speed assuming most of the hardcore math is done using JNI*.

*) JNI aka Java Native Interface, a way to use external dynamic libraries aka DLL's or .so's.

I would say that coding in Java is easier than in C++ but quite a lot of that comes from IDE. When you code Java there is not many reasons not to use Eclipse, most the best opensource IDE and perhaps even best of all IDE's
Another thing that makes Java easier is huge standard library. Basically there isn't many things that aren't already there. If it isn't then most certainly there is some library that you can use. E.g for OpenGL there is jogl, for OpenAL there is joal etc.

Two things I miss in Java are true templates and operator overloading.

That is not operator overloading, that is function overloading

Dont confuse programming with scripting.

C++ can be used for both, most others can't.

I always thought it might be possible to make a programming language with a grammer structured after Latin, but I never sat down and worked out the details.
I may someday, just for the fun of it.

That's not really the sort of thing I had in mind though.

Yay! A language flamewar in the making.
Here's my opinion:
C / C++ -> good
Java -> Bad
Python -> Ok
everything else -> don't care / don't know

And so, as people typically say in these sorts of threads: Use the right language for the job. Different languages are good for different things. For example, I use [my favourite language] for [almost everything], and [my second favourite language] for [a couple of other less important things].

Ok, my point is that it doesn't really matter much which language you use. Most languages can do basically everything. Pick the right language for the job; and if you don't know which language is the right one, just pick the language you are most comfortable with.

Im a C++ programmer myself (or so i like to think), but after a three courses of java at uni, i must say that java has it's merits.
It is a lot easier, for many reasons, including; no memory management, no messing around with header guards, circular dependencies etc, the API is HUGE and have functions for reading and drawing bitmaps, playing sounds etc, it has a more human-readable syntax (extends instead of : ), has two types of for-loops, it has interfaces and it has eclipse which will make you cry when you use Dev-C++ again

It is however quite the memory hog, and all users will need the RTE, preferably the latest version if you want to use generics (and you do).

As for C++, i'd say that it's THE language of choice for game-makers everywhere. The industry uses it. There is fast and easy access to hw-rendering etc.

Basically, Java is a sleek sport car (with a dvd player for when you are stuck in trafic) and C++ is a 18 wheel diesel truck.

They both have their uses. Java is great if you want to make a GUI application quickly or a smaller game, while C++ would be great if you want to make a high-performance 3D game.

This is all imo naturally

I'd say the other way around.

Yeah but in his post he said Java is a memory hog (size) as well as it's standard set of API that comes with it (is big too).

And to me, C++ is a cooler language, sports cars are cool , but they can crash easily with an amateur driver. With rigs, their crashes would be destructive (if the JVM crashed maybe?)

Of course, if you want to keep your sanity, ignore what I just said.

A sport car is not very fuel effective, it is however full of fluffy and shiny things.
An 18 wheeler is tough, powerful and effective. But it aint pretty.

That was the thought behind my analogy.

... 2k/XP clean up memory leaks automatically. This is why I can go for months on end without rebooting.