Java SQL update syntax error

I have a function "update" on my server and I call it through "btnUpdateActionPerformed" on my client. I'm performing an update on two tables, namely "patient" and "insurance" but when I run it, the following error is displayed on server side:

Error1: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE patient_id = 3' at line 1

Below are the codes for update:

public String update(int patient_id, String first_name ,String last_name, String date_of_birth, String gender, String address, int contact_number, 
        String occupation, String nic_number, String marital_status, String r_first_name, String r_last_name, String r_occupation, int r_contact_number, 
        int room_number,int doctor_id_assigned,int nurse_id_assigned,int company_id,String company_name,String company_address,
        int phone_number, String policy_group) throws RemoteException{
        try{
            Class.forName("com.mysql.jdbc.Driver");
            con= DriverManager.getConnection("jdbc:mysql://localhost/hospital","root","");
            String patient_sql = "UPDATE patient SET first_name = ?, last_name = ?, date_of_birth = ?, gender = ?, address = ?, contact_number = ?,"
                    + " occupation = ?, nic_number = ?, marital_status = ?, r_first_name = ?, r_last_name = ?, r_occupation = ?, r_contact_number = ?, "
                    + "room_number = ?, doctor_id_assigned = ?, nurse_id_assigned = ?, company_id = ?,  WHERE patient_id = ?";
            ps=con.prepareStatement(patient_sql);
            ps.setString(1, first_name);
            ps.setString(2, last_name);
            ps.setString(3, date_of_birth);
            ps.setString(4, gender);
            ps.setString(5, address);
            ps.setInt(6, contact_number);
            ps.setString(7, occupation);
            ps.setString(8, nic_number);
            ps.setString(9, marital_status);
            ps.setString(10, r_first_name);
            ps.setString(11, r_last_name);
            ps.setString(12, r_occupation);
            ps.setInt(13, r_contact_number);
            ps.setInt(14, room_number);
            ps.setInt(15, doctor_id_assigned);
            ps.setInt(16, nurse_id_assigned);
            ps.setInt(17, company_id);
            ps.setInt(18, patient_id);
            ps.executeUpdate();

            String insurance_sql = "UPDATE insurance SET company_name = ?, company_address = ?, phone_number = ?, policy_group = ? WHERE company_id = ?";
            ps=con.prepareStatement(insurance_sql);
            ps.setString(1, company_name);
            ps.setString(2, company_address);
            ps.setInt(3, phone_number);
            ps.setString(4, policy_group);
            ps.setInt(5, company_id);
            ps.executeUpdate();

            con.close();
        }
        catch(SQLException e){
            System.out.println("Error1: "+e);
        }
        catch(ClassNotFoundException e){
            System.out.println("Error2: "+e);
        }
        return "updated";
}

The codes for btnUpdateActionPerformed:

private void btnUpdateActionPerformed(java.awt.event.ActionEvent evt){                                          
    try{
        Registry reg = LocateRegistry.getRegistry("localhost",5022);
        ClerkInterface ci = (ClerkInterface)reg.lookup("clerk");
        int patient_id = Integer.parseInt(txtPatientId.getText());
        String first_name = txtFirstName.getText();
        String last_name = txtLastName.getText();
        String date_of_birth = txtDateOfBirth.getText();
        String gender="";
        if(radMale.isSelected()){
            gender = "Male";
        }
        else if(radFemale.isSelected()){
             gender = "Female";
        }
        String address = txtAddress.getText();
        int contact_number = Integer.parseInt(txtContactNumber.getText());
        String occupation = txtOccupation.getText();
        String nic_number = txtNICNumber.getText();
        String marital_status = txtNICNumber.getText();
        String r_first_name = txtRFirstName.getText();
        String r_last_name = txtRLastName.getText();
        String r_occupation = txtROccupation.getText();
        int r_contact_number = Integer.parseInt(txtRContactNumber.getText());
        int room_number = Integer.parseInt(txtRoomNumber.getText());
        int doctor_id_assigned = Integer.parseInt(txtDoctorIdAssigned.getText());
        int nurse_id_assigned = Integer.parseInt(txtNurseIdAssigned.getText());
        int company_id = Integer.parseInt(txtCompanyId.getText());
        String company_name = txtCompanyName.getText();
        String company_address = txtCompanyAddress.getText();
        int phone_number = Integer.parseInt(txtCompanyPhoneNumber.getText());
        String policy_group = txtPolicyGroup.getText();

        ci.update(patient_id, first_name, last_name, date_of_birth, gender, address, contact_number, occupation, nic_number, marital_status, 
                r_first_name, r_last_name, r_occupation, r_contact_number, room_number, doctor_id_assigned, nurse_id_assigned, company_id,
                company_name, company_address, phone_number, policy_group);

        JOptionPane.showMessageDialog(null,"Patient updated");
    }
    catch(RemoteException e){System.out.println("Error: "+e.getMessage());}
    catch(NotBoundException e){System.out.println("Error: "+e.getMessage());}
}