Error - Can't create a java class file by intelliJ

# Problem

I can't make java class file in this directory. Why?

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# Situation

After made a project with site(https://start.spring.io/) and I've just opened my project by intelliJ.

I created the package 03datastruct under the temp directory, then I can't choose the java class file in that package.

(There isn't java class file type for making recommendation. But Kotlin file is available.)

 

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# Cause

I broke the package naming rules.

The name must not start with a number. e.g. 03datastructure, 04mergesort

besides, IDE warned me when I create the package name like this screenshot

but I haven't noticed..

 

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# Solution

All you have to do is name the package begins with letter.

(You can add a number at the middle or the end of the name.)

 

Also, The Icon named starts letter is different to package icon named start number.

There are hole in the disket.

 

 

So I can make java class file in the package :)