Question enthuware.ocejws.v6.2.204: wrong answer?

[socialguy]

Given the following JAX-RS client:

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public class URLConClient { 
  public static void main(String[] args) throws IOException {
      URL restURL = new URL("http://localhost:8080/SimpleRS/jax/rs/add/5/6");
      URLConnection connection = (URLConnection) restURL.openConnection();
     // 1
     readFrom(connection);
  } 
}

What are connection setup methods that can be in line //1?

connection.setRequestMethod("GET");
connection.setDoInput(true);
connection.setReadTimeout(10000);
connection.setDoOutput(true);
connection.setDoInput(false);

connection.setDoOutput(true) is not required as we're not writing out anything from the client. The explanation says the same thing as well but still it's marked as one of the correct options. Why?

[fjwalraven]

connection.setDoOutput(true) is not required as we're not writing out anything from the client. The explanation says the same thing as well but still it's marked as one of the correct options. Why?

You are right, setDoOutput(true) is not required. It is a bit of trick question though.

Basically it doesn't harm calling this method. Note that the question states: "What are connection setup methods that can be in line //1?". It is not stating "should" or "must".

The options connection.setDoInput(false) and the connection.setRequestMethod("GET") do harm.

Regards,
Frits

[socialguy]

Thanks. You may want to update the answer explanation in the simulator to what you said here; it's a little confusing there because it just states that the method call is not needed. Leaves the reader wondering why the answer is correct then.

[fjwalraven]

Good point!

I have changed the explanation.

Thanks,
Frits

[himaiMinh]

One more point, it is optional to have this

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connection.setDoInput(true)

According to MZ's notes, the flag for setDoInput is true by default. If the client wants to get input, this line of code can be omitted. According to MZ, "The client code will be able to read HTTP response by default."

One more interesting finding,usually most examples from books do this:

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//The fully qualified name is java.net.HttpURLConnection
HttpURLConnection connection = (HttpURLConnection) restURL.openConnection();

But in this question, the connection is URLConnection:

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//URLConnection is an abstract class and I wonder what connection's concrete type is....
URLConnection connection = (URLConnection)restURL.openConnection();

Then, I do this

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 System.out.println(connection.getClass().getName());

The output is : sun.net.www.protocol.http.HttpURLConnection

[himaiMinh]

Another point is, I think it does not harm to put

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 connection.setAllowUserInteraction (true);

It compiles, but it is just not necessary.

[fjwalraven]

One more interesting finding,usually most examples from books do this:

Code: Select all

//The fully qualified name is java.net.HttpURLConnection
HttpURLConnection connection = (HttpURLConnection) restURL.openConnection();

But in this question, the connection is URLConnection:

Code: Select all

//URLConnection is an abstract class and I wonder what connection's concrete type is....
URLConnection connection = (URLConnection)restURL.openConnection();

Then, I do this

Code: Select all

 System.out.println(connection.getClass().getName());

The output is : sun.net.www.protocol.http.HttpURLConnection

The HttpURLConnection extends URLConnection and both (!) classes are abstract.

Regards,
Frits