Compatibility mode between Java and Node.js clients is not fully in place yet, but we're improving it as we speak. So, data that's put with a Node.js client can't be retrieved by Java client and viceversa.
I've created HRJS-41 that would add a compatibility marshaller that'd enable Node.js client to potentially read Strings that are formatted following same method as default Java Hot Rod client marshaller...
However, there's a possible workaround here. You can configure the Java Hot Rod client to use a marshaller that produces UTF-8 String representations, in which case, the Node.js client would be able to read data fine.
ConfigurationBuilder clientBuilder = ...