Ide-idea-problem

.java The lower right corner of the file is red j

After research and inquiry , This is mainly because there is no setting output The path of , The file cannot be compiled , So red appears in the lower left corner of the class file .

File Open in project structure find Modules, One of the Sources, Put the first one on the right X Click on , Get rid of Root After path , To add , As shown in the figure below ：

specify the output path in configure project 

The error occurred from github On checkout When your project . Because the configuration file is not uploaded together , So it's running java There is an error in the program .

In fact, this error is because there is no setting output The path of , Just change the settings in two places ： 
1. stay Modules Check... In the settings ”Inherit project compile path” 

2. Set up Project Medium ”Project compiler output” 
 

choice ”Project The path of ”+”\out”, For example, mine is