A DESCRIPTION OF THE PROBLEM : quote: "Beyond dates and times, the API also allows the storage of period and durations of time." comment: replace "period" with "periods" quote: "A Period expresses an amount of time in units meaningful to humans, such as years or hours." comment: replace "hours" with "days" URL OF FAULTY DOCUMENTATION : http://docs.oracle.com/javase/8/docs/api/java/time/package-summary.html