java - Trouble with order of reading next line with Scanner

The difference in execution, with change in orders, is due to the fact that new-line is not consumed by nextInt(), nextDouble(), next() or nextFoo() methods.

Therefore, whenever you place a call to nextLine() after any of those methods, it consumes that newline, and virtually skips over that statement.

The fix is simple, don't use nextFoo() methods before nextLine(). Try :-

i2 = Integer.parseInt(scan.nextLine());
d2 = Double.parseDouble(scan.nextLine());
s2 = scan.nextLine();

Or else, you could consume the new-line by

i2 = scan.nextInt();

d2 = scan.nextDouble();
scan.nextLine(); //---> Add this before the nextLine() call
s2 = scan.nextLine();

Order#3 works fine, as nextLine() is the first statement, and therefore, there are no left-over characters to consume.

Related: Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo() methods