String Concatenation, Join, Replace 메소드

• join()

String.join("아딴 믄자를 합칠 것인지", "덧붙이고 싶은 것들")
	ex : String.join(",","2","3","4")
		"2,3,4"

• replace()

"abcd".replace("ab", "xyz")
	"xyzcd"