JPA Method
in jakarta.persistence.Graph

Subgraph<K> addMapKeySubgraph(
  MapAttribute<?superT,K,?> attribute
)


Add a node to the graph that corresponds to a map key that is a managed type. This allows for construction of multi-node entity graphs that include related managed types.
Parameters:
attribute - attribute
Return:
subgraph for the key attribute
Throws:
IllegalArgumentException - if the attribute's target type is not a managed type entity
IllegalStateException - if this EntityGraph has been statically defined
Since:
JPA 3.2