JAVA: MultivaluedMap for adding multiple value in Map | javax.ws.rs JAX-RS API

#MultivaluedMap #Headers #JAX-RS
What is MultivaluedMap? is it part of JDK library?
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Important Debugging information and short cut keys
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► Debugging is the routine process of locating and removing bugs, errors or abnormalities from programs. It's a must-have skill for any Java developer because it helps to find a subtle bug that is not visible during code reviews or that only happens when a specific condition occurs.
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Sample Code of MultlivaluedMap
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package Com.techtalk.collection;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MultivaluedHashMap;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;

public class MultiValueMapExample {

public static void main(String[] args) {

Client client = null;
WebTarget tb = client.target("http://www.xyz.com/api");

MultivaluedMap(String,Object) header = new MultivaluedHashMap();
header.add("Content-Type", "application/json");
header.add("accept", "application/json");
header.add("Security-Id", "9872138uijoiwe");
header.add("Reques-Id", "jkhjhasd-213231");

Response res = tb.request().headers(header).get();
System.out.println(res.getStatus());

}
}

The MultivaluedMap interface does not belong to "Java", meaning that the interface is not a part of the core libraries. It is a part of the javax.ws.rs hierarchy which is part of the JAX-RS specification. It is used by frameworks implementing the specification such as Jersey. It is used whenever maps should refer to not only a single value but to any number of values. An example for the use would be for example the storage of a request header where you one might want to add several values per key. Or even no keys in some cases where it is easier to handle an empty list compared to a null value.

Take this HTTP-header for example:

Accept-Encoding: compress;q=0.5, gzip;q=1.0

You would model this by

MultivaluedMap(String, String) map = ...
map.add("Accept-Encoding", "compress;q=0.5");
map.add("Accept-Encoding", "gzip;q=1.0");

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