arraylist contains method not working properly

in the chargelist i have got charges of 162,666,888

      for(int i=0;i<charge.length;i++)
            {
                  if(charge[i]==null || charge[i].trim().length()==0)
                        continue;
                  houseDocumentCharges                                                            = new HouseDocumentCharges();
                  houseDocumentCharges.costIncurredAt                        = StringUtility.getDefault(costIncurredAt[i],"D");
                  houseDocumentCharges.chargeId                                    = StringUtility.noNull(charge[i]);
                  houseDocumentCharges.chargeDescription                  = StringUtility.noNull(chargeDescription[i]);
                  chargesList.add(houseDocumentCharges);
            }

if the chargeId's having costIncurredAt is 'O' i  dont want to enter in to the if loop


666 chargeid is having  costIncurredAt is 'O'  still enter into the if loop ;

if 888 chargeid has costIncurredAt is 'D' should enter into if loop;i have written below but it didnt solve my purpose.

        if(chargeList!=null && chargeList.size()>0)
            {
    if (!chargeList.contains( new HouseDocumentCharges("620","O")) )
    {
                        userInputModel = new UserInputModel(validMap,"vendorCode",      ValidationConstants.MULTI_VENDOR_VALIDATION_NAME,5);//modified validation code from 2 to 5
                        validationModel.addUserInput("vendorId",userInputModel);
    }
    }


HouseDocumentCharges classs
****************************

      public HouseDocumentCharges(String chargeId,String costIncurredAt) {
       this.chargeId = chargeId;
        this.costIncurredAt = costIncurredAt;
   }

 public HouseDocumentCharges(String chargeId) {
       this.chargeId = chargeId;
        }
  public boolean equals(Object obj) {
       return chargeId.equals(((HouseDocumentCharges)obj).chargeId) || costIncurredAt.equals(((HouseDocumentCharges)obj).costIncurredAt);
   }
   public int hashCode() {
       return chargeId.hashCode();
   }