Summary of identifiers and keywords — hope not to make mistakes again.

（(1) table of Java key words

A total of 50 key words are shown below.

Most of the keywords were agreed upon at the beginning of the Java syntax release, and a few were added with the development of the Java language.  
strictfp JDK1.2 Join
assert JDK1.4 Join
enum JDK5.0 Join
There are a few words that do not have a clear grammatical meaning, but the Java language also stipulates that it is a keyword, and with the development of Java, it may be given grammatical meaning in the future. These key words are also called reserved keywords, such as keyword list.In the tableconst、goto 。

 

String Not keyword

（Two) identifier

　　Class names (including interfaces, enumerations, Abstract classes), method names, variables, constants, package names, etc. can be customized character combinations.  
Although it can be customized, the following rules should be followed:

 　　

1. It is composed of letters, underlines, numbers, and $symbols.

2. You can only begin with letters, underlines, and $symbols, and cannot start with numbers.

3. The length of the identifier is not limited.

4. Case sensitive

5. It can’t be a keyword.

 

 Summary: for the concept, we must have a clear understanding and not feel it. A clear grasp of concepts is conducive to further learning new knowledge and understanding principles.