Just a small heads up on this issue: YearMonth custom type and attribute converter implementations are provided in Vlads recent blog post https://vladmihalcea.com/java-yearmonth-jpa-hibernate/ as well as his Hibernate custom types repository: https://github.com/vladmihalcea/hibernate-types/tree/master/hibernate-types-52/src/main/java/com/vladmihalcea/hibernate/type/basic