rest-assured/src/main/java/io/restassured/builder/ResponseSpecBuilder.java
public ResponseSpecBuilder registerParser(String contentType, Parser parser) {
        spec.parser(contentType, parser);
        return this;
    }
public ResponseSpecBuilder registerParser(String contentType, Parser parser) {
        spec.parser(contentType, parser);
        return this;
    }
Register a content-type to be parsed using a predefined parser. E.g. let's say you want parse
content-type <tt>application/vnd.uoml+xml</tt> with the XML parser to be able to verify the response using the XML dot notations:
<pre>
expect().body("document.child", equalsTo("something"))..
</pre>
Since <tt>application/vnd.uoml+xml</tt> is not registered to be processed by the XML parser by default you need to explicitly
tell REST Assured to use this parser before making the request:
<pre>
expect().parser("application/vnd.uoml+xml", Parser.XML").when(). ..;
</pre>
<p/>
You can also specify by default by using:
<pre>
RestAssured.registerParser("application/vnd.uoml+xml, Parser.XML");
</pre>

@param contentType The content-type to register
@param parser      The parser to use when verifying the response.
@return The builder