Question ablut B&S project's BOOK operation.

[Wills Ni]

1.In the instruction is said that

The User Interface
It must allow the user to book a selected record, updating the database file accordingly.

What's meaning of "book"?It means input into the "owner" field? or other operation?

2.How to realize "Thread safety"?
Synchronizing a hashmap object in the lock and unlock methods is having resolved the problem?

[Russell Wurth]

What's meaning of "book"?It means input into the "owner" field? or other operation?

Yes, you should allow the user to put an ID in that field, effectively flagging the record/row as booked. Your instructions should explain whether this is numeric or alphanumeric.

2.How to realize "Thread safety"?
Synchronizing a hashmap object in the lock and unlock methods is having resolved the problem?[/QB]

Yes, you are correct.