The correct syntax would be to surround the hosts with quotes and seperate multiple hosts with a | character.
eg for system configuration "localhost|127.0.0.1|10.*.*.*|etc"
e.g. -Dhttp.nonProxyHosts="localhost|127.0.0.1|10.*.*.*|etc"
Note: When using DNS name a fully qualified name is required as they will not work with a wild card.
Example:
-Dhttp.nonProxyHosts="www.foo.com"
Not
-Dhttp.nonProxyHosts="*.foo.com"