GUI
Jar to exe
Error afhandeling
Dialog
Remove string part
Read files in folder
Java dialog
Message dialogen
showMessageDialog
Teaching Swing
Java Programming Style Guide
gradient_backgrounds
Togglebutton
Github material ui
https://www.google.com/imgres?imgurl=https%3A%2F%2Fwindows-cdn.softpedia.com%2Fscreenshots%2FVisual-JavaSWING-Components-Library_3.png&imgrefurl=https%3A%2F%2Fwww.softpedia.com%2Fget%2FProgramming%2FComponents-Libraries%2FVisual-JavaSWING-Components-Library.shtml&docid=bJOup8eN7CLomM&tbnid=6mj0HAujdnVioM%3A&vet=10ahUKEwjUpOCU7crgAhWLGuwKHWlcB4QQMwhGKAcwBw..i&w=670&h=550&bih=901&biw=1901&q=java%20gradient%20button%20no%20border&ved=0ahUKEwjUpOCU7crgAhWLGuwKHWlcB4QQMwhGKAcwBw&iact=mrc&uact=8
http://www.javaknowledge.info/custom-jbutton-with-gradient-color/