Explanation:
If a table was accidentally truncated or there was a logic error in the application, it can cause a user process failure. If a user process terminates, then the process monitor (PMON) background process intervenes, which saves the DBA some time and effort. PMON is here to handle automatic process recovery for the database: when PMON detects the process failure, PMON rolls back the failed process and releases locks on the tables.
Incorrect Answers:
2: If the user issues an abnormal interrupt, it does not cause a user process failure.
4: If application program receives an addressing exception it's application error, not user one.
5: It's media failure if there is a head crash on the disk containing a database file.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 656
Chapter 14: Database Failure and Recovery

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