Package: is actually a folder, used to solve the same name problem characteristics: All the letters are lowercase letters single layer: Itcast Multilayer: Itcast.20150628.day01 class or interface features: One word: uppercase, other letter lowercase multiple words: The first letter of each word is capitalized, The other letter lowercase name consists of a word: Demo \ Hello name consists of multiple words: HelloWorld \ Hellojava method and variable features: first letter lowercase, starting with the second word, first letter uppercase, and other letters are lowercase names by a word: meth The OD () name consists of multiple words: Createmethod () \ ShowMessage () constant feature: All uppercase letters, multiple words using an underscore to split _ name by a word: Age, SEX name by multiple words: student_age \ S Tudent_name_age
Identifiers (common naming rules)
