import static javax.persistence.FetchType.LAZY;

import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.IdClass;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.MappedSuperclass;
import javax.persistence.Transient;


@MappedSuperclass
@IdClass(AcePK.class)
public abstract class Ace {

    protected FilterRule filterRule;

    @ManyToOne(cascade = {}, fetch = LAZY, targetEntity = FilterRule.class)
    @JoinColumn(name = "RULE_UUID", referencedColumnName="UUID",
                updatable = false, nullable = false )
    @Id
    public FilterRule getFilterRule() {
        return this.filterRule;
    }

    public boolean setFilterRule(FilterRule rule) {
        this.filterRule = rule;
    }


    private String grantedTo;

    @Column(name = GRANTED_TO, nullable = false, length = 36)
    @Id
    public String getGrantedTo() {
        return this.grantedTo;
    }

    public void setGantedTo(String value) {
        this.grantedTo = value;
    }
}

import java.io.Serializable;

import javax.persistence.Column;


public class AcecPK implements Serializable {

    private static final long serialVersionUID = -4837448484343854819L;

    public String filterRule;
    public String grantedTo;

    @Column(name = "RULE_UUID", length = 36) //I've tried with and without including this annotation; the result within the db is always the same
    public String getFilterRule() {
        return filterRule;
    }

    public void setFilterRule(String rule) {
        this.filterRule = rule;
    }


    public String getGrantedTo() {
        return grantedTo;
    }

    public void setGrantedTo(String granted) {
        this.grantedTo = granted;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        AcePK acePK = (AcePK) o;

        if (filterRule != null ? !filterRule.equals(acePK.filterRule) : acePK.filterRule != null) {
            return false;
        }
        if (grantedTo != null ? !grantedTo.equals(acePK.grantedTo) : acePK.grantedTo != null) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        int result = filterRule != null ? filterRule.hashCode() : 0;
        result = 31 * result + (grantedTo != null ? grantedTo.hashCode() : 0);
        return result;
    }
}