Java HelloWorld hint "error: Main class HelloWorld not found or cannot be loaded" solution

After checking the environment variables and other prerequisites, pay attention to Classpath, still reported "error: Cannot find or Load main class HelloWorld".

My Project catalog:Mygs-maven/src/main/java/hello

Under the Hello directory:

Greeter.java Helloworld.java

Project Code:
Helloworld.java

 Package Hello;   Public class HelloWorld {    publicstaticvoid  main (string[] args) {          New  Greeter ();        System.out.println (Greeter.sayhello ());}    }

Greeter.java

 Package Hello;   Public class Greeter {    public  String SayHello () {        return "Hello world!" ;    }}

Note the red area, Greeter.java Helloworld.java Two classes are added to the Hello package.
Execute the Java class command to add a package name.

[Email protected] java]$ cd/home/nx/workspace/web_back-end/spring/mygs-maven/target/classes/[Email Protected] classes]$ java hello. HelloWorld HelloWorld!

Here, Java's Novice readers may also be aware of why, and here is no longer the explanation.

Java HelloWorld hint "error: Main class HelloWorld not found or cannot be loaded" solution