2018-07-09 11:40:24.816  INFO 20196 --- [localhost:27017]
org.mongodb.driver.cluster               : Exception in monitor thread while
connecting to server localhost:27017

com.mongodb.MongoSocketOpenException: Exception opening socket
at com.mongodb.connection.SocketStream.open(SocketStream.java:62) ~[mongo-
java-driver-3.6.4.jar:na]
at com.mongodb.connection.InternalStreamConnection.open
(InternalStreamConnection.java:126) ~[mongo-java-driver-3.6.4.jar:na]
at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run
(DefaultServerMonitor.java:114) ~[mongo-java-driver-3.6.4.jar:na]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_171]
Caused by: java.net.ConnectException: Connection refused (Connection refused)
at java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:1.8.0_171]
at
java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
~[na:1.8.0_171]
at java.net.AbstractPlainSocketImpl.connectToAddress
(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_171]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
~[na:1.8.0_171]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_171]
at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_171]
at com.mongodb.connection.SocketStreamHelper.initialize
(SocketStreamHelper.java:59)
~[mongo-java-driver-3.6.4.jar:na]
at com.mongodb.connection.SocketStream.open(SocketStream.java:57) ~[mongo-
java-driver-3.6.4.jar:na]
... 3 common frames omitted

2018-07-09 11:40:25.164  INFO 20196 --- [           main]
org.mongodb.driver.cluster               : Cluster description not yet
available.
Waiting for 30000 ms before timing out