Add original exception as cause to keep the stacktrace
refactoring: remove control flow by exception
remove compiler warning and use List and not Vector
remove auto-generated todos from test main()
Use List and not Vector
use String.indexOf(char) which is faster than String.indexOf(String)
use not deprecated method
Don't create instances of already existing BigInteger
Don't use toString() on String objects
Organize imports and remove useless overriding of method -> just calling super.method()
Remove redundant modifiers
refactoring: reducing method length
refactoring: reducing method length