Here is an example of how to use the JsonNodeDeserializer class from the Jackson Databind library to deserialize a JsonNode from JSON:

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer;

import java.io.IOException;

public class CustomJsonNodeDeserializer extends JsonNodeDeserializer {

    @Override
    public JsonNode deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
        JsonNode node = super.deserialize(p, ctxt);
        // Do some custom processing on the JsonNode
        return node;
    }
}

You can then use this custom deserializer by registering it with the ObjectMapper:

ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addDeserializer(JsonNode.class, new CustomJsonNodeDeserializer());
mapper.registerModule(module);

Then you can deserialize your JSON to JsonNode as follow:

JsonNode jsonNode = mapper.readValue(jsonString, JsonNode.class);

Please note that the above example is just a skeleton code, you may need to handle the exception and add proper validation based on your use case.

You can also use the JsonNodeDeserializer class directly to deserialize your json to JsonNode without creating the custom deserializer.

JsonNode jsonNode = mapper.readTree(jsonString);

This will directly parse the json and give you the JsonNode representation of the json.