PeerGroup: Limit number of Bitcoin network peers at re-connect after …

…connection loss

Cherry pick e112b13
Cherry pick 093d5e4
Cherry pick cbac863

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

@@ -588,7 +588,12 @@ public void go() {
                     executor.schedule(this, delay, TimeUnit.MILLISECONDS);
                     return;
                 }
-                connectTo(addrToTry, false, vConnectTimeoutMillis);
+
+                // BitcoinJ gets too many connections after a connection loss and reconnect as it adds up a lot of
+                // potential candidates and then try to connect to all of those when getting connection again.
+                // A check for maxConnections is required to not exceed connections.
+                if(pendingPeers.size() + peers.size() < maxConnections)
+                    connectTo(addrToTry, false, vConnectTimeoutMillis);
             } finally {
                 lock.unlock();
             }