getDeclaredId(type) - JPA IdentifiableType's method

Return the attribute that corresponds to the id attribute declared by the entity or mapped superclass.
type - the type of the represented declared id attribute
declared id attribute
IllegalArgumentException - if id attribute of the given type is not declared in the identifiable type or if the identifiable type has an id class
JPA 2.0

This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
ObjectDB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.