[GSS] Thread used by LoadBalancer remains when connection to kie-server fails during instantinating of KieServicesClient

When KieServicesClient fails to connect to KieServer, LoadBalancer is invoked to check availability of server like the following.

[2019/01/24 18:19:38.411] [pool-1-thread-1] [DEBUG] (LoadBalancer.java:149) - Starting to scan if any of the failed endpoints is back online
org.kie.server.common.rest.NoEndpointFoundException: No available endpoints found
at org.kie.server.client.balancer.impl.AbstractBalancerStrategy.checkEmpty(AbstractBalancerStrategy.java:27)
at org.kie.server.client.balancer.impl.RoundRobinBalancerStrategy.next(RoundRobinBalancerStrategy.java:37)
at org.kie.server.client.balancer.LoadBalancer.getUrl(LoadBalancer.java:52)
at org.kie.server.client.impl.AbstractKieServicesClientImpl.invoke(AbstractKieServicesClientImpl.java:809)
at org.kie.server.client.impl.AbstractKieServicesClientImpl.makeHttpGetRequestAndCreateServiceResponse(AbstractKieServicesClientImpl.java:177)
at org.kie.server.client.impl.KieServicesClientImpl.getServerInfo(KieServicesClientImpl.java:159)
at org.kie.server.client.impl.KieServicesClientImpl.getCapabilitiesFromServer(KieServicesClientImpl.java:132)
at org.kie.server.client.impl.KieServicesClientImpl.init(KieServicesClientImpl.java:87)
at org.kie.server.client.impl.KieServicesClientImpl.<init>(KieServicesClientImpl.java:74)
at org.kie.server.client.KieServicesFactory.newKieServicesClient(KieServicesFactory.java:101)
at com.sample.rules.test.KieServerRestClientTest.connectionFailureTest(KieServerRestClientTest.java:55)

But after that, the thread used by LoadBalancer remains until termination of client application as LoadBalancer.close() is not called.