Do we intend to created a separate execute method for each method call? Or have one and pass the HTTP method calls to it. 
So why do you think this way is better?
Option 1: .executeUrl(KEY_HTTP_XXXX_METHOD, param);
or 
Option 2: 
apiReader.executeGetUrl(requestProperties);
apiReader.executePostUrl(requestProperties);
apiReader.executePutUrl(requestProperties);

More methods mean duplications and more maintenance!