Hello I am new in this forum and in working with Arduino.
My question is, if it is possible that I can controll my arduino Uno with a GUI which was written in Java but the things what the arduino should do is written in C.
For example i made a GUI in Java where i can press a button, but the code which says that the LED should blink is written in C.
Is it possible that C and Java are working together?
Sorry for my bad english 
The current IDE is written in Java too, and Arduino is programmed in C/C++ so it is working already.
Thank you for your fast answer.
Just i know that it works, now i have to find the way how it works
Communication between a PC application and an Arduino usually use a serial port on the PC that communicates with the Arduino through the USB system. That's how the Arduino IDE communicates with an Arduino. You can carry on simple communication using the Serial Monitor in the IDE.
Then you could write a PC program (in whatever language you like) to do the job of the Serial Monitor. Once you have mastered that you should have no problem extending the concept to do more complex stuff.
My preferred PC programming system is JRuby which is built on the Java VM. I use the RXTXcomm serial library.
...R
Thank you,
So I am going to try to master it.