Compiling and running Java files cannot be found or the main class cannot be loaded

Here is a possible solution to the program that contains the package keyword, "Unable to find or cannot load the main class" When using terminal to run the program.

For example, the program name is Helloworldtest.java, and the program contains the package HelloWorld statement, which is located in the Javatest directory, which is Javatest/helloworld/helloworldtest.java.

You should run the JAVAC directive in the same directory as the Java file, running Javac in the HelloWorld directory Helloworldtest.java

Run the Java directive in the upper directory where the package resides , running Java helloworld.helloworldtest in the Javatest directory

Because it is Java that is studied in OS X environment, it is not familiar with the setting of Classpath and so on, perhaps this method is the same meaning as part of the main answer.

Gu Zhifang
Links: https://www.zhihu.com/question/36537093/answer/206814470
Source: Know
Copyright belongs to the author.  Commercial reprint please contact the author for authorization, non-commercial reprint please specify the source. Https://www.cnblogs.com/Ring1981/p/6240412.html //这个问题原因有以下几种,但是和环境变量并没有太大的关系 //能够执行java 和 javac 就证明你的环境变量已经配置好了,其实 classpath 可以不配置 //假如有如下文件:H:\code\Hello.java public class Hello{      public static void main(String[]args){          System.out.println( "Hello" );      } } //正确编译命令: javac Hello.java //正确运行命令: java Hello 错误 1 :H:\code>java Hello.java 错误: 找不到或无法加载主类 Hello.java 原因:命令错误 错误 2 :H:\code>java Hello. class 错误: 找不到或无法加载主类 Hello. class 原因:命令错误 错误 3 :java 源文件带有包名,往往容易出错 如:H:\code\Hello2.java package com.example; public class Hello2{      public static void main(String[]args){          System.out.println( "Hello2" );      } } 这代码看上去没什么问题,执行: H:\code>javac Hello2.java H:\code>java Hello2 错误: 找不到或无法加载主类 Hello2 解决办法: +.删除包名  或者  +.在code 下创建一个与包名相同的文件结构(H:\code\com\example\Hello2.java)    编译:H:\code>javac com/example/Hello2.java    运行:H:\code>java com.example.Hello2

Compiling and running Java files cannot be found or the main class cannot be loaded