The problem

Classes should not be declared inside package-info.java files.

Typically package-info.java contains only a package declaration, preceded immediately by the annotations on the package. While the file could technically contain the source code for one or more classes with package access, it would be very bad form.

– JLS 7.4

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("PackageInfo") to the enclosing element.