Have you worked with tables organized in a hierarchical structure?

Yes, experience working with tables organized in a hierarchical structure is common when dealing with data where elements have parent-child relationships, such as product categories, organizational structures, or comments with replies.

In Java, such structures are usually represented using models with a parentId field or a list of child elements. Recursive queries are used to work with such tables (if supported by the DBMS), or a tree is built in memory.

Example of a class for a hierarchy node:

public class Category {
    private Long id;
    private String name;
    private Category parent;
    private List<Category> children = new ArrayList<>();

    // getters and setters
}

When loading data, the children field can be filled recursively to obtain the tree.