why do we use system.out.print ln() why we use ln just for line??

Answer 1

Java language focus on security of data
to avoid unwanted data to get printed or displayed
it has made some rules.
system.out means something is going out of the program and print is to display on the content on screen.

when u write all that in one line than only you wll be able to display hello ! on screen

Answer 2

ln of println is for printing next statements in a new line.
when using just System.out.print(); next print statements are printed in the same line.