Time comparison

With Java 8+, you can use the new Java time API:

• to parse the time:

  LocalTime time = LocalTime.parse("11:22")
  

• to do date comparisons, you have LocalTime::isBefore and LocalTime::isAfter - note that these methods are strict

So you problem would be as simple as:

public static void main(String[] args) {
  LocalTime time = LocalTime.parse("11:22");
  System.out.println(isBetween(time, LocalTime.of(10, 0), LocalTime.of(18, 0)));
}

public static boolean isBetween(LocalTime candidate, LocalTime start, LocalTime end) {
  return !candidate.isBefore(start) && !candidate.isAfter(end);  // Inclusive.
}

For inclusive beginning but exclusive ending (half-open), use this line.

return !candidate.isBefore(start) && candidate.isBefore(end);  // Exclusive of end.

Java doesn't (yet) have a good built-in Time class (it has one for JDBC queries, but that's not what you want).

One option would be use the JodaTime APIs and its LocalTime class.

Sticking with just the built-in Java APIs, you are stuck with java.util.Date. You can use a SimpleDateFormat to parse the time, then the Date comparison functions to see if it is before or after some other time:

SimpleDateFormat parser = new SimpleDateFormat("HH:mm");
Date ten = parser.parse("10:00");
Date eighteen = parser.parse("18:00");

try {
    Date userDate = parser.parse(someOtherDate);
    if (userDate.after(ten) && userDate.before(eighteen)) {
        ...
    }
} catch (ParseException e) {
    // Invalid date was entered
}

Or you could just use some string manipulations, perhaps a regular expression to extract just the hour and the minute portions, convert them to numbers and do a numerical comparison:

Pattern p = Pattern.compile("(\d{2}):(\d{2})");
Matcher m = p.matcher(userString);
if (m.matches() ) {
    String hourString = m.group(1);
    String minuteString = m.group(2);
    int hour = Integer.parseInt(hourString);
    int minute = Integer.parseInt(minuteString);

    if (hour >= 10 && hour <= 18) {
        ...
    }
}

It really all depends on what you are trying to accomplish.