- System.out : output
- System.in : input
- System.exit(0) : use stop program
- System.gc() : delete garbage object
- System.nanoTime() : current time
- System.currentTimeMillis() : current time
- Ex_ System.exit(0)
- Ex_ System.nanoTime(), System.currentTimeMilis()
25. 컴퓨터학과 졸업 / SQLD, 정보처리기사 취득