[immutability-refactor] All these members are only assigned on constructors/declaration.

Avoid mutability as much as possible, it's the devil.

core/src/main/java/io/bitsquare/alert/AlertManager.java

@@ -40,8 +40,8 @@ public class AlertManager {
     transient private static final Logger log = LoggerFactory.getLogger(AlertManager.class);
 
     private final AlertService alertService;
-    private KeyRing keyRing;
+    private final KeyRing keyRing;
-    private User user;
+    private final User user;
     private final ObjectProperty<Alert> alertMessageProperty = new SimpleObjectProperty<>();
 
     // Pub key for developer global alert message

core/src/main/java/io/bitsquare/alert/AlertService.java

@@ -33,7 +33,7 @@ import javax.inject.Inject;
  */
 public class AlertService {
     private static final Logger log = LoggerFactory.getLogger(AlertService.class);
-    private P2PService p2PService;
+    private final P2PService p2PService;
 
 
     ///////////////////////////////////////////////////////////////////////////////////////////

core/src/main/java/io/bitsquare/arbitration/ArbitratorService.java

@@ -37,7 +37,7 @@ import java.util.stream.Collectors;
 public class ArbitratorService {
     private static final Logger log = LoggerFactory.getLogger(ArbitratorService.class);
 
-    private P2PService p2PService;
+    private final P2PService p2PService;
 
     interface ArbitratorMapResultHandler {
         void handleResult(Map<String, Arbitrator> arbitratorsMap);

core/src/main/java/io/bitsquare/btc/AddressEntry.java

@@ -56,7 +56,7 @@ public class AddressEntry implements Serializable {
 
     // Only set if its a TRADE Context
     @Nullable
-    private String offerId;
+    private final String offerId;
 
     private final Context context;
     private final byte[] pubKey;

core/src/main/java/io/bitsquare/locale/CurrencyUtil.java

@@ -27,7 +27,7 @@ import java.util.stream.Collectors;
 public class CurrencyUtil {
     transient private static final Logger log = LoggerFactory.getLogger(CurrencyUtil.class);
 
-    private static List<TradeCurrency> allSortedCurrencies = createAllSortedCurrenciesList();
+    private static final List<TradeCurrency> allSortedCurrencies = createAllSortedCurrenciesList();
 
     public static List<TradeCurrency> getAllSortedCurrencies() {
         return allSortedCurrencies;

core/src/main/java/io/bitsquare/payment/SepaAccountContractData.java

@@ -38,7 +38,7 @@ public class SepaAccountContractData extends PaymentAccountContractData implemen
     private String iban;
     private String bic;
     // Dont use a set here as we need a deterministic ordering, otherwise the contract hash does not match
-    private ArrayList<String> acceptedCountryCodes;
+    private final ArrayList<String> acceptedCountryCodes;
 
     public SepaAccountContractData(String paymentMethod, String id, int maxTradePeriod) {
         super(paymentMethod, id, maxTradePeriod);

core/src/main/java/io/bitsquare/trade/TradeManager.java

@@ -83,7 +83,7 @@ public class TradeManager {
     private final Storage<TradableList<Trade>> tradableListStorage;
     private final TradableList<Trade> trades;
     private final BooleanProperty pendingTradesInitialized = new SimpleBooleanProperty();
-    private FirstPeerAuthenticatedListener firstPeerAuthenticatedListener;
+    private final FirstPeerAuthenticatedListener firstPeerAuthenticatedListener;
 
 
     ///////////////////////////////////////////////////////////////////////////////////////////

core/src/main/java/io/bitsquare/trade/offer/OfferBookService.java

@@ -35,7 +35,7 @@ import java.util.stream.Collectors;
 public class OfferBookService {
     private static final Logger log = LoggerFactory.getLogger(OfferBookService.class);
 
-    private P2PService p2PService;
+    private final P2PService p2PService;
 
 
     ///////////////////////////////////////////////////////////////////////////////////////////

core/src/main/java/io/bitsquare/trade/offer/OpenOfferManager.java

@@ -58,8 +58,8 @@ public class OpenOfferManager {
     private static final Logger log = LoggerFactory.getLogger(OpenOfferManager.class);
 
     private final KeyRing keyRing;
-    private User user;
+    private final User user;
-    private P2PService p2PService;
+    private final P2PService p2PService;
     private final WalletService walletService;
     private final TradeWalletService tradeWalletService;
     private final OfferBookService offerBookService;

core/src/main/java/io/bitsquare/user/PopupId.java

@@ -21,9 +21,9 @@ public class PopupId {
 
     // We don't use an enum because it would break updates if we add a new item in a new version
 
-    public static String TRADE_WALLET = "tradeWallet";
+    public static final String TRADE_WALLET = "tradeWallet";
-    public static String SEND_PAYMENT_INFO = "sendPaymentInfo";
+    public static final String SEND_PAYMENT_INFO = "sendPaymentInfo";
-    public static String PAYMENT_SENT = "paymentSent";
+    public static final String PAYMENT_SENT = "paymentSent";
-    public static String PAYMENT_RECEIVED = "paymentReceived";
+    public static final String PAYMENT_RECEIVED = "paymentReceived";
 
 }

core/src/main/java/io/bitsquare/user/Preferences.java

@@ -88,14 +88,14 @@ public class Preferences implements Serializable {
     private boolean useAnimations = true;
     private boolean useEffects = true;
     private boolean displaySecurityDepositInfo = true;
-    private ArrayList<TradeCurrency> tradeCurrencies;
+    private final ArrayList<TradeCurrency> tradeCurrencies;
     private BlockChainExplorer blockChainExplorerMainNet;
     private BlockChainExplorer blockChainExplorerTestNet;
     private boolean showPlaceOfferConfirmation;
     private boolean showTakeOfferConfirmation;
     private String backupDirectory;
     private boolean autoSelectArbitrators = true;
-    private Map<String, Boolean> showAgainMap;
+    private final Map<String, Boolean> showAgainMap;
     private boolean tacAccepted;
     private Locale preferredLocale;
     private TradeCurrency preferredTradeCurrency;