Use of keywords, identifiers, Javadoc tools

Identifiers: Some names in Java programs can be customized, so these custom names are referred to as custom identifiers. The

specifier takes note of the details:
    1, the constituent element of the identifier is a letter (A-Z, A-Z), a number (0-9), an underscore (_), a dollar sign ($).
    2, identifiers cannot start with a number
    3, identifiers are strictly case-sensitive
    4, and the length of identifiers is no length limit
    5, the name of the identifier is generally meaningful (to make people see the name of understanding)
    6, cannot be used for custom identifiers

Custom identifier specification:
    1, class name, and interface list words are capitalized in the first letter, and other words are lowercase.
    2, variable names and method names are all lowercase, and the first letter of the other words is capitalized.
    3, package name all words lowercase.
    4, constant all words uppercase, words and words separated by an underscore such as: up_direction

Keyword: A keyword is an identifier that has a special meaning in a Java program. Keywords are typically used to describe the structure of a program or to represent a data type.

Javadoc Tool use format

    javadoc-d The path to the document    source file for  java

Javadoc Tools to pay attention to the details
    1, if a class needs to use the Javadoc tool to generate a software development document, then the class must use the public adornment
    2, The content of a document comment comment is generally a specification of a

that is written in the upper part of a class or method:
     General line comments are located on the right side of the code, and multiple lines of comments and documentation comments are generally written on top of the class or method.

Keywords, identifiers, use of Javadoc tools