@Override
			protected Cache createCache() {
				return cache;
			}
To test the custom DNS, should to add vm arguments as below:
-Dsun.net.spi.nameservice.provider.1=dns,LocalManagedDnsProxy
-Dngrinder.etc.hosts=10.0.0.1:www.google.com,10.0.0.2:www.google2.com.

@author JunHo Yoon
ngrinder-runtime/src/test/java/org/ngrinder/dns/LocalManagedDnsTest.java