<hibernate-mapping>
    <class name="com.wg.common.bean.ExamMedicalDecision" table="exam_medical_decision">
        <id name="id" type="integer">
            <column name="id" />
            <generator class="sequence">
                <param name="sequence">exam_medical_decision_id_seq</param>
            </generator>
        </id>
...
        <one-to-one name="diagnosisAndOptions1" cascade="all" lazy="false">
           <formula>1</formula>
           <formula>id</formula>
        </one-to-one>
        <one-to-one name="diagnosisAndOptions2" cascade="all" lazy="false">
           <formula>2</formula>
           <formula>id</formula>
        </one-to-one>
        <one-to-one name="diagnosisAndOptions3" cascade="all" lazy="false">
           <formula>3</formula>
           <formula>id</formula>
        </one-to-one>
        <one-to-one name="diagnosisAndOptions4" cascade="all" lazy="false">
           <formula>4</formula>
           <formula>id</formula>
        </one-to-one>
    </class>
</hibernate-mapping>

<hibernate-mapping>
    <class name="com.wg.common.bean.ExamDiagnosisAndManagementOptions" table="exam_diagnosis_and_management_options" >
        <composite-id >
           <key-property name="index" type="integer">
              <column name="index" not-null="true"></column>
           </key-property>
           <key-many-to-one name="examMedicalDecision" class="com.wg.common.bean.ExamMedicalDecision">
              <column name="exam_medical_decision_id" not-null="true"></column>
             </key-many-to-one>
        </composite-id>
        <many-to-one name="diagnosticCode" class="com.wg.common.bean.DiagnosticCode" lazy="false">
            <column name="diagnostic_code_id"/>
        </many-to-one>
        <set name="options" table="exam_diagnosis_and_management_options_xref" lazy="false">
           <key>
              <column name="exam_diagnosis_and_management_options_index" not-null="true"></column>
              <column name="exam_diagnosis_and_management_options_emd_id" not-null="true"></column>
           </key>
           <element column="exam_management_option" type="text" not-null="true"/>
        </set>
    </class>
</hibernate-mapping>

public class ExamDiagnosisAndManagementOptionsId implements Serializable {

    private volatile Integer index;
    private volatile ExamMedicalDecision examMedicalDecision;
    public Integer getIndex() {
        return index;
    }
    public void setIndex(Integer index) {
        this.index = index;
    }
    public ExamMedicalDecision getExamMedicalDecision() {
        return examMedicalDecision;
    }
    public void setExamMedicalDecision(ExamMedicalDecision emd) {
        this.examMedicalDecision = emd;
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result
            + ((examMedicalDecision == null) ? 0 : examMedicalDecision.hashCode());
        result = prime * result + ((index == null) ? 0 : index.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        ExamDiagnosisAndManagementOptions other = (ExamDiagnosisAndManagementOptions) obj;
        if (examMedicalDecision == null) {
            if (other.getExamMedicalDecision() != null) return false;
        }
        else if (!examMedicalDecision.equals(other.getExamMedicalDecision())) return false;
        if (index == null) {
            if (other.getIndex() != null) return false;
        }
        else if (!index.equals(other.getIndex())) return false;
        return true;
    }
}