IntelliJ Community IDE. If you create a class, and your squared brackets are not present in your Main method, after the “String” argument type, (String args), then the .class file will not be created because the .java file with the your class name will not compile (you may not even see it, even if there is a class within the IDE), your run button will be grayed out, and the errors "Main class not found and “Current file not runnable” will be produced. So place the squared brackets and RECOMPILE THE CLASS under the BUILD MENU. This should create the .class file from the .java file and place it in the corresponding folders. If, however, you cannot find the created .class file afterward, simply click the RUN MENU > Edit Configurations and tell the IDE where the newly created .class file is. It should pop up for you after a few seconds in the next window, or on that next window click “Project” and then locate the class because it will be there. How it helps everyone.