Table home_codes ID | code 10 | 123 20 | 456 30 | 456 35 | 999 40 | 777 45 | 999

The question provides a table called home_codes with two columns: ID and code.

If the task is, for example, to find all records with duplicate code values, you can use an SQL query with grouping:

SELECT code, COUNT(*) as count
FROM home_codes
GROUP BY code
HAVING COUNT(*) > 1;

This query will show codes that occur more than once (for example, 456 and 999).

If you need to get all rows where code is duplicated:

SELECT *
FROM home_codes
WHERE code IN (
    SELECT code
    FROM home_codes
    GROUP BY code
    HAVING COUNT(*) > 1
);

In Java, to work with such data, you can use JDBC or ORM, such as JPA/Hibernate, to execute such a query and process the results.

If you need a more specific solution — specify the task.