https://docs.oracle.com/javase/7/docs/api/java/lang/package-summary.html java.lang (Java Platform SE 7 ) Interface Summary Interface Description Appendable An object to which char sequences and values can be appended. AutoCloseable A resource that must be closed when it is no longer needed. CharSequence A CharSequence is a readable sequence of char values. docs.oracle.com java.lang 패키지/오토박싱 자바는 ..