remove lock synchronization in connection service to avoid blocking

core/src/main/java/haveno/core/api/XmrConnectionService.java

@@ -125,15 +125,12 @@ public final class XmrConnectionService {
     public void onShutDownStarted() {
         log.info("{}.onShutDownStarted()", getClass().getSimpleName());
         isShutDownStarted = true;
-        synchronized (lock) {
-            // ensures request not in progress
-        }
     }
 
     public void shutDown() {
-        log.info("Shutting down started for {}", getClass().getSimpleName());
+        log.info("Shutting down {}", getClass().getSimpleName());
-        synchronized (lock) {
         isInitialized = false;
+        synchronized (lock) {
             if (daemonPollLooper != null) daemonPollLooper.stop();
             connectionManager.stopPolling();
             daemon = null;
@@ -162,95 +159,71 @@ public final class XmrConnectionService {
     }
 
     public void addConnection(MoneroRpcConnection connection) {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         if (coreContext.isApiUser()) connectionList.addConnection(connection);
         connectionManager.addConnection(connection);
     }
-    }
 
     public void removeConnection(String uri) {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionList.removeConnection(uri);
         connectionManager.removeConnection(uri);
     }
-    }
 
     public MoneroRpcConnection getConnection() {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         return connectionManager.getConnection();
     }
-    }
 
     public List<MoneroRpcConnection> getConnections() {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         return connectionManager.getConnections();
     }
-    }
 
     public void setConnection(String connectionUri) {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionManager.setConnection(connectionUri); // listener will update connection list
     }
-    }
 
     public void setConnection(MoneroRpcConnection connection) {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionManager.setConnection(connection); // listener will update connection list
     }
-    }
 
     public MoneroRpcConnection checkConnection() {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionManager.checkConnection();
         return getConnection();
     }
-    }
 
     public List<MoneroRpcConnection> checkConnections() {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionManager.checkConnections();
         return getConnections();
     }
-    }
 
     public void startCheckingConnection(Long refreshPeriod) {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionList.setRefreshPeriod(refreshPeriod);
         updatePolling();
     }
-    }
 
     public void stopCheckingConnection() {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionManager.stopPolling();
         connectionList.setRefreshPeriod(-1L);
     }
-    }
 
     public MoneroRpcConnection getBestAvailableConnection() {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         return connectionManager.getBestAvailableConnection();
     }
-    }
 
     public void setAutoSwitch(boolean autoSwitch) {
-        synchronized (lock) {
         accountService.checkAccountOpen();
         connectionManager.setAutoSwitch(autoSwitch);
         connectionList.setAutoSwitch(autoSwitch);
     }
-    }
 
     public boolean isConnectionLocal() {
         return isConnectionLocal(getConnection());
@@ -665,6 +638,7 @@ public final class XmrConnectionService {
                 }
 
                 new Thread(() -> {
+                    if (isShutDownStarted) return;
                     if (!isFixedConnection() && connectionManager.getAutoSwitch()) {
                         MoneroRpcConnection bestConnection = getBestAvailableConnection();
                         if (bestConnection != null) connectionManager.setConnection(bestConnection);