hi there, how can i display an error message in java and stop compile program at that point of the error?

Use try catch block for this purpose

how do i do that???

try{
// code that you want to run
}
catch(NullPointerException nEx){
// what you want it to do or show when a nullpointerexception occurs
}
catch(Exception ex){
// what has to be done in case of another exception
}

a more simple form (the simplest) of this structure is:

try{
// actual code
}
catch(Exception ex){
// what has to be done in case of any exception
}