I am reading here, that
On connect, the JVM (Java Virtual Machine) tries to resolve the hostname to IP/port. Windows tries a netbios ns query on UDP (User Datagram Protocol) port 137 with a timeout of 1.5 seconds, ignores any ICMP (Internet Control Message Protocol) port unreachable packets and repeats this two more times, adding up to a value of 4.5 seconds. I suggest putting critical hostnames in your HOSTS file to make sure they are resolved quickly. Another possibility is turning off NETBIOS altogether and running pure TCP/IP on your LAN (Local Area Network).
is this currently an issue still? Because I am working on a heartbeat-sensor and I was curious.