Hibernate Static Inner

ID

java.hibernate_static_inner

Severity

low

Remediation Complexity

trivial

Remediation Risk

low

Remediation Effort

low

Resource

Reliability

Language

Java

Tags

hibernate, orm

Description

Reports @Entity annotations on non-static inner classes. Hibernate requires persistent inner classes to be declared static because a non-static inner class holds an implicit reference to the enclosing instance, which cannot be serialized or persisted.

Rationale

Reliability — Hibernate throws a MappingException at startup when attempting to map a non-static inner class as an entity.

Remediation

Non-compliant code

public class Outer {
    @Entity
    class Inner { // non-static inner class
        @Id private Long id;
    }
}

Compliant code

public class Outer {
    @Entity
    static class Inner { // static inner class
        @Id private Long id;
    }
}

References