Using @EmbeddedId with JpaRepository

(by Yosi Lev)
This can be done as the following:
Suppose your main entity is:

@Entity
@Table(name="JRULES_FLOW")
public class JrulesFlow implements Serializable {
   private static final long serialVersionUID = 1L;

   @EmbeddedId
   private JrulesFlowPK id;

   @Column(name="NEXT_SEQ")
   private int nextSeq;

   @Column(name="REF_ID")
   private String refId;

   @Column(name="TASK_TYPE")
   private String taskType;

   @Column(name="VALUE_TO_FIND")
   private String valueToFind;
}

And your PK class is :

@Embeddable
public class JrulesFlowPK implements Serializable {
   //default serial version id, required for serializable classes.
   private static final long serialVersionUID = 1L;

   @Column(name="FLOW_ID")
   private String flowId;

   @Column(name="TASK_SEQ")
   private long taskSeq;
 }

The JPA repository method name shouls include the name of the id field in
the main class followed by the property you want to query uppon within the PK class:

public interface JrulesFlowRepository extends JpaRepository<JrulesFlow, 
      JrulesFlowPK> { // NOTE: put here both classes - also the pk class..
   public List<JrulesFlow>  findByIdFlowId(String flowId);  // Id - is the 
                  // @EmbeddedId in JrulesFlow. FlowId is an attribute 
                  // within JrulesFlowPK
}