Yes, yes, and no.

Yes, you need the Java runtime (or at least some implementation of it) to run Java apps.

Yes, you need the Flash Player to run Flash/ActionScript based apps. Note that you can export the Flash app as an actual executable instead of running it in the browser and requiring the Flash Player (much like how N does it) (in this case, the Flash Player and the Flash app are pretty much mixed together into one executable).

And no, the Flash Player doesn't interpret the source code to run the application. Well, not quite. Both Java and ActionScript are compiled to "bytecode." Then the runtime (i.e. the Java runtime or Flash Player) will read the bytecode and either turn the bytecode into actual machine code and execute it, or it will read the bytecode and "interpret" the bytecode. But neither of them actually read and interpret the raw source.

What is Java technology and why do I need it?

Java is a programming language and computing platform first released by Sun Microsystems in 1995. It is the underlying technology that powers state-of-the-art programs including utilities, games, and business applications. Java runs on more than 850 million personal computers worldwide, and on billions of devices worldwide, including mobile and TV devices.

Why do I need Java?

There are lots of applications and websites that won't work unless you have Java installed, and more are created every day. Java is fast, secure, and reliable. From laptops to datacenters, game consoles to scientific supercomputers, cell phones to the Internet, Java is everywhere!

http://www.java.com/en/download/faq/whatis_java.xml

Everybody should have Java Runtime in their computer and if not then get it. Updating your Java Runtime Environment would be a good idea, too. Windows OS users should look into this especially because Microsoft does not aggressively support. ( Throat clearing here )

Java is quite powerful, regardless if the programmer likes to use it or not. If you can effectively learn to program with precompiling or Just In Time (JIT) compiling when appropriate, then you have very good performance competitive in the league with the best out there. The Java system is built for cross-platform implementations to be as easy as possible, which is much of the reason why billions of devices run it. By contrast, Microsoft makes you jump through hoops and you still fall short with Common Language Runtime of the .NET Framework in full cross-platform implementation (Saying this to show advantage in using Java). Sure there is OpenGL in any case, but with Java Runtime Environment one stage of work is eliminated.

Look into jMonkey, by the way.

You can embed a JRE in your program distribution, that way, end-users won't need to have Java installed.

You should read up about the "Java environment" before deploying any application. It will probably save you a few headaches while researching something.

That means, what "byte code" is, whats a Java Virtual Machine (interpreted languages and "Just-in-time" compilation concepts would be nice too), what are the different editions of Java (Java EE, Java SE, Java ME), whats the Java Development Kit, whats the "Java Native Interface", and so on.

Its not to complicate your life but to make it easier later when you're researching more complex things.

You can convert your JARs into EXEs using Jarsplice or similar tools, but it is fair to assume most people will either have java or wont have a problem if your installer prompts an installation of the JRE.

You can convert your JARs into EXEs using Jarsplice or similar tools, but it is fair to assume most people will either have java or wont have a problem if your installer prompts an installation of the JRE.

This used to be true; not so much any more, at least so far as Apple goes. Apple has outright disabled Java on newer releases due to security problems.... or at least, that's the excuse Apple gave. I honestly wouldn't be surprised to see Microsoft follow suit. When you've got the Department of Homeland Security telling people to disable/remove Java, that's all encouragement Microsoft needs... if their lawyers give them the go-ahead that is.

Java is still out there on all platforms, it's just not quite so simple to assume its there as it was even a year ago.

The Java scare reminds me of the ActiveX fright back years when many more people then lacked good anti-malware or did stupid things like turn off User Account Control because they read about it or their friends said that it makes everything much easier to install - LOL.

If a person has good anti-virus software and manages the computer the way they should, then all threats are nearly eliminated.

You can convert your JARs into EXEs using Jarsplice or similar tools, but it is fair to assume most people will either have java or wont have a problem if your installer prompts an installation of the JRE.

This used to be true; not so much any more, at least so far as Apple goes. Apple has outright disabled Java on newer releases due to security problems.... or at least, that's the excuse Apple gave. I honestly wouldn't be surprised to see Microsoft follow suit. When you've got the Department of Homeland Security telling people to disable/remove Java, that's all encouragement Microsoft needs... if their lawyers give them the go-ahead that is.

Java is still out there on all platforms, it's just not quite so simple to assume its there as it was even a year ago.