Polydnj wrote:I'm practising loops, methods, classes, variable, arrays which are all standard to Java, no matter what device I use right?. I guess that the purpose of using a libraries is to communicate with other hardware, like you said "in the physical world".
There are extension libraries for more complex/specialised software-only applications as well, but the default libraries (packages) that come with Java are pretty extensive to get started with. So no need for extra libraries for some time
After what you listed there, I'd suggest looking into the default packages:
- java.util (collections / 'advanced data types')
- java.text (date and other formats)
- java.math (big numbers)
- java.io (file input/output)
...these are all pretty much platform independent / portable stuff.