Specification for names in Java

Package Name: All letters are lowercase when multiple words are composed.

Xxxyyyzzz

Class name Interface name: When multiple words are composed, the first letter of all words is capitalized.

Xxxyyyzzz

Variable name and function name: When multiple words are composed, the first letter is lowercase, and the second word starts with the first letter of each word capitalized.

Xxxyyyzzz

Constant name: All letters are capitalized. For multiple words, each word is connected with an underscore.

Xxx_yyy_zzz

Specification for names in Java