A.publicStringBufferdelete(intstart,intend) B.publicStringBufferappend(數(shù)據(jù)類型str) C.publicStringBufferreverse() D.publicStringsubstring(intstart,intend)
A.concat() B.append() C.reverse() D.deleteCharAt()
A.String類能被繼承 B.獲取String對象的長度用length()方法 C.String類繼承自O(shè)bject D.字符串存在字符串常量池中