Java Design Issue: Enforce method call sequence

Question

There is a question which was recently asked to me in an interview.

Problem: There is a class meant to profile the execution time of the code. The class

Answer 1

As Per Interview question ,It seems to like this

Class StopWatch {

    long startTime;
    long stopTime;
    public StopWatch() {
    start();
    }

    void start() {// set startTime}
    void stop() { // set stopTime}
    long getTime() {
stop();
// return difference

}

}

So now All user need to create object of StopWatch class at beginning and getTime() need to call at End

For e.g

StopWatch stopWatch=new StopWatch();
//do Some stuff
 stopWatch.getTime()