Here's part of the code in Category.java
public class Category
{
static public final class range
{
public range( double lower, double upper )
{
this.lower = lower;
this.upper = upper;
}
public double lower;
public double upper;
}
static public Map< category_type, range > validCategoryRanges = new EnumMap<>(category_type.class);
...
When access is needed in other files of same package, there's no such class, only field validCategoryRanges is seen. (In Eclipse it worked).