Question

I want my program to tell the user that if (s)he enters a non-integer he should try again, instead of just terminating the whole main method like it does now. Pseudo code of problem part:

int integer = input.nextInt();
If (user types in a non-integer) { 
  ("you have entered a false value, please retry");
  then let's user enter int value
else {
  assign nextint() to integer and continue
}

Answer 1

You can use a while loop to re-execute that portion of code until the user enters a proper integer value.

do {
    input = read user input
} while(input is not an integer)

It seems you are using a Scanner, so you could use the hasNextInt method:

while (!input.hasNextInt()) {
    let user know that you are unhappy
    input.next(); //consume the non integer entry
}

//once here, you know that you have an int, so read it
int number = input.nextInt();