what is dao layer structure?

testlsb - beans, bo, dao

suppose LoginBo.java

package testlab.bo;
public interface LoginBo {
    boolean validateLogin(String name,String password,String user_type);
}

or testdetailBo.java
/*
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 * and open the template in the editor.
 */
package testlab.bo;
import java.util.List;
import javax.faces.model.SelectItem;
import testlab.beans.TestDetailBean;
/**
 *
 * @author ANURAGBIS
 */
public interface TestDetailBo {
    List<SelectItem> branchDetail(TestDetailBean testDetailBean);
    List<SelectItem> sampleTypeDetail(TestDetailBean testDetailBean);
    String submitReport(TestDetailBean testDetailBean);
    String submitUpdateReport(TestDetailBean testDetailBean);
    void uploadPdf(TestDetailBean testDetailBean);
    void uploadUpdatePdf(TestDetailBean testDetailBean);
    List<TestDetailBean> searchTestByText(TestDetailBean testDetailBean);
    void fetchTestDetailBySampleId(TestDetailBean testDetailBean, int sampleid);
    String deleteTest(TestDetailBean testDetailBean, int sampleid);
    List<TestDetailBean> viewTestbyText(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestbyType(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestbyDateText(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestBwDate(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestForBranchbyText(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestForBranchbyDateText(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestForBranchbyType(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestForBranchBwDate(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestForMgrBwDate(TestDetailBean testDetailBean);
    List<TestDetailBean> fetchSelectedLabTestDetailForMgrBwTwoDateByLabcode(TestDetailBean testDetailBean, String labcode);
    List<TestDetailBean> fetchSelectedISNOTestDetailForMgrBwTwoDateByisno(TestDetailBean testDetailBean, String isno);
    List<TestDetailBean> fetchAllLabTestDetailForMgrBwTwoDate(TestDetailBean testDetailBean);
    List<TestDetailBean> fetchAllISNOTestDetailForMgrBwTwoDate(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestReportForLabOfSevenDays(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestReportForBranchOfSevenDays(TestDetailBean testDetailBean);
    List<TestDetailBean> viewTestReportForMngrOfSevenDays(TestDetailBean testDetailBean);
   
    List<TestDetailBean> viewCompTestReportForMngr(TestDetailBean testDetailBean);
}