在setter和getter中获取NULL-JAVA

Question

i always end up with this error "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException" when im running my program. i have Member Class where i code my setter and getter. All the entities i need id there. now i have another method in "Admin Class"

 public class Admin {
     private ArrayList<Member> members;
     private String AccessName;
     private String username;
     private String password;

     public Admin(){
        this.AccessName="Ms. April Santos";
        this.username = "estella";
        this.password = "teller";
        this.members = new ArrayList<Member>();
    }

    public ArrayList<Member> getMembers() {
        return members;
    }

    public void setMembers(ArrayList<Member> members) {
        this.members = members;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getAccessName() {
        return AccessName;
    }

    public void setAccessName(String AccessName) {
        this.AccessName=AccessName;;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final Admin other = (Admin) obj;
        if ((this.username == null) ? (other.username != null) : !this.username.equals(other.username)) {
            return false;
        }
        return true;
    }

    @Override
    public int hashCode() {
        int hash = 7;
        hash = 97 * hash + (this.username != null ? this.username.hashCode() : 0);
        return hash;
    }

    @Override
    public String toString() {
        return "Admin{" + "members=" + members + ", AccessName;=" + AccessName + ", username=" + username + ", password=" + password + '}';
    }

       public Member searchMember(Member member){
        return this.searchMember(member.getMemberId());
    }

         public Member searchMember(String memberId){
          for(Member member : this.members){
            if(member.getMemberId().equals(memberId)){
                return member;
            }
          }
          return null;
    }

    public Member addMember(Member member){
        if (this.searchMember(member) == null){
            this.members.add(member);
            return member;
        }
        return null;
    }

    public Member addMember(String memberId, String firstName,String middleName, String lastName){
        if (this.searchMember(memberId) == null){
            Member member = new Member(memberId, firstName,middleName, lastName);
            this.members.add(member);
            return member;
        }
        return null;
    }

    public boolean validateLogin(String username, String password){
        boolean valid = false;
        valid = this.username.equals(username) && this.password.equals(password);
        return valid;
    }

   }

now im calling public addMember(String memberId, String firstName,String middleName, String lastName) in my AddMemberView(GUI). im trying to get all the text in the textfield/combobox and set it so that it will be temporary saved and ready to be saved in database as i code my DAO. this is my AddMemberView btnSave action look:

 import java.sql.SQLException;
 import java.text.*;
 import java.util.*;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javax.swing.JOptionPane;
 import rtu.tomis.bom.Admin;
 import rtu.tomis.bom.Member;
 import rtu.tomis.dao.MemberDao;

 public class AddMemberView extends javax.swing.JPanel {

 private MainFrameView mainFrameView;
 private Member member;
  private Admin admin;

  AddMemberView(Member memb, Admin admin){

    this.member= memb;
    this.admin= admin;

}

public AddMemberView() {
    initComponents();
}

  public AddMemberView(MainFrameView mf) {
    this.mainFrameView = mf;
    initComponents();
}

    public AddMemberView(Member m) {
    this.member = m;
    initComponents();
}

  private void btnSaveActionPerformed(java.awt.event.ActionEvent evt) {                                        
    String memberid = (this.txtMembersID.getText());
    String fname= (this.txtFirstName.getText());
    String mname=(this.txtMiddleName.getText());
    String lname=(this.txtLastName.getText());
    if(this.admin.addMember(memberid, fname,mname, lname) != null)//im having null here
    {
       try{
            member = this.admin.searchMember(memberid);// and if i remove that 1st line of null. the next null pointer is here
            String month = (String)cmbMonth.getSelectedItem();
            Integer day = (Integer) cmbDay.getSelectedItem();
            Integer year = (Integer)cmbYear.getSelectedItem();
            String bday = month + " " + day + ", " + year;
            DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.US);
            Date dateBday = df.parse(bday);
            String Block = this.txtBlkLotNo.getText();
            String Street = (String)this.cmbStreet.getSelectedItem();
            String Brgy=(String)this.cmbBarangay.getSelectedItem();
            String City= (String)this.cmbCity.getSelectedItem();
            String Address = Block + " " + "" + Street + " ," +  Brgy + " ," + City;
            String Full = fname + " " + mname + " " + lname;
            int age= Integer.parseInt(this.txtAge.getText());
            int contact = Integer.parseInt(this.txtContact.getText());
            String region =(String) this.cmbRegion.getSelectedItem();

            this.member.setFirstName(fname);// then if i remove the two my next null line is here and those who have this.**member**.setblabla.
            this.member.setMiddleName(mname);
            this.member.setLastName(lname);
            this.member.setFullname(Full);
            this.member.setLotNo(Block);
            this.member.setBarangay(Brgy);
            this.member.setCity(City);
            this.member.setFulladdress(Address);
            this.member.setBirthday(dateBday);
            this.member.setAge(age);
            this.member.setEmailAddress(this.txtEadd.getText());
            this.member.setVotersId(this.txtVotersID.getText());
            this.member.setContactNo(contact);
            this.member.setRegion(region);
            this.member.setMemberId(memberid);
           if(this.rbtnFemale != null){
               this.member.setGender(this.rbtnFemale.getLabel());
           }
               else{
               this.member.setGender(this.rbtnFemale.getLabel());
           }

       }catch (ParseException ex) {
            System.out.println("Exception: "+ ex.getMessage());
        }
        JOptionPane.showMessageDialog(this, "Info saved!");
        JOptionPane.showMessageDialog(this,"Name" + this.member.getFirstName());

    }

}                  

thanks for your help.

Answer 1

I think your "admin" variable is null. Do you call your constructor? If yes, are the parameters correct?

Just write "private Admin admin" dont make the admin variable an Admin Object. Try initialize it or call the constructor properly.