PeerGroup.addAddress(): Don't increase max connections if address already exists.

core/src/main/java/org/bitcoinj/core/PeerGroup.java

@@ -860,22 +860,26 @@ public class PeerGroup implements TransactionBroadcaster {
         int newMax;
         lock.lock();
         try {
-            addInactive(peerAddress);
+            if (addInactive(peerAddress)) {
                 newMax = getMaxConnections() + 1;
+                setMaxConnections(newMax);
+            }
         } finally {
             lock.unlock();
         }
-        setMaxConnections(newMax);
     }
 
-    private void addInactive(PeerAddress peerAddress) {
+    // Adds peerAddress to backoffMap map and inactives queue.
+    // Returns true if it was added, false if it was already there.
+    private boolean addInactive(PeerAddress peerAddress) {
         lock.lock();
         try {
             // Deduplicate
             if (backoffMap.containsKey(peerAddress))
-                return;
+                return false;
             backoffMap.put(peerAddress, new ExponentialBackoff(peerBackoffParams));
             inactives.offer(peerAddress);
+            return true;
         } finally {
             lock.unlock();
         }