Strange situation

[rafael.osipov]

I have a mobile device: Nokia 9300.

And I have created an application to work with HTTPConnections.

When I try to load a data via HTTPConnection I get the following error message:

java.lang.ClassNotFoundException: com/symbian/midp/io/protocol/Http/Protocol

I used only standard J2ME classes. And my app works fine on Motorola phones, for example. But on Nokia 9300 I get this error.

Below there is a part of my code that causes the problem:

final HttpConnection shopsHttpConnection = (HttpConnection)Connector.open(cmdGetShops);
final InputStream shopsLoadingStream = shopsHttpConnection.openInputStream();
final InputStreamReader shopsLoadingStreamReader = new InputStreamReader(shopsLoadingStream, ENCODING);

Any ideas ?

Thank you.

[hartti]

so are you using java.microedition.io.HttpConnection or are you trying to import some other classes? Which method call throws the exception? What is the URL in the cmdGetShops variable? Have you tried without final keyword?

Hartti

[rafael.osipov]

I used only standard java2me classes. No additional libraries for networking were used. Only java.io.* and javax.microedition.io.* classes.

------------------------------------------------
Code that causes exception is marked as bold.
------------------------------------------------

final String HTTP_COMMAND_SUFFIX_GET_SHOPS = "/ShopsListXML?OpenPage";

final SettingsModel settingsModel = SettingsModel.getInstance();

final String cmdGetShops = settingsModel.getServerAddress() + HTTP_COMMAND_SUFFIX_GET_SHOPS;

final InputConnection shopsHttpConnection = (InputConnection)Connector.open(cmdGetShops);
final InputStream shopsLoadingStream = shopsHttpConnection.openInputStream();

------------------------------------------------

Use of final keyword should not lead to such problems. I tried with and without final keyword - the whole picture is the same.

cmdGetShops address looks like: http://www.server.com/ShopsListXML?OpenPage
When an application accesses server by this address server returns XML result to be parsed.

I suspect the problem occurs because some components are missing on the device operating system.

I compiled this application by Sun java compiler (version 1.4).

I tried to run this application on Motorola RAZR V3 (CLDC 1.0, MIDP 2.0). On Motorola's device this application works ok. But on Nokia 9300 - fails.

I would like to understand the source of the problem. And how to avoid it.

[peterblazejewicz]

hi rafael,

can you try to run standard Sun's http sample precompiled jars that come with WTK installation on that phone? they will allow you to check if problem is with phone or with your implementation,

regards,
Peter

[rafael.osipov]

I tried standard http demo midlet. It does work ok.

I will compare this example with my code.

thank you.

[rafael.osipov]

Code in sample and my code are semantically identical.

But the problem had an unexpected source.


I have a text field in Settings screen: serverAddressField

This field declared as:

TextField serverAddressField = new TextField("Server address:",
settingsModel.getServerAddress(),
MAX_SERVER_ADDRESS_SYMBOLS,
TextField.URL);

TextField.URL flag allows to specify CAPITAL letters in URL too.

And when a user specifies any http address the first letter in word "http" is adding as a capital letter. And instead of "http://www.server.com" we have "Http://www.server.com".

And this big first letter H in server address causes the problem.

To resolve this - I just needed to convert address to lower case letters.

[peterblazejewicz]

hi Rafael,

well, we learn both something: "protocol" is found by class lookup and it need to be lowercase, if we provide "Http" runtime error is thrown,

sample code:

void getHttpConnection() throws Exception {
String url = "Http://www.yahoo.com/";
HttpConnection c = null;
InputStream is = null;
try {
c = (HttpConnection)Connector.open(url);
is = c.openInputStream();
// do something with data
get_resultsForm().setString("::no errors::");
}catch (Exception ex){
get_resultsForm().setString("::ERROR::\n");
get_resultsForm().setString(ex.toString());
throw new Exception(ex.getMessage());
} finally {
if (is != null)
is.close();
if (c != null)
c.close();
}
}

it will throw exception:

.........
java.lang.ClassNotFoundException: com/sun/midp/io/j2me/Http/Protocol
at javax.microedition.io.Connector.openPrim(Connector.java:292)
at javax.microedition.io.Connector.open(Connector.java:219)
at javax.microedition.io.Connector.open(Connector.java:187)
at javax.microedition.io.Connector.open(Connector.java:169)

that means that we need to extract "protocol" part from an url and make it lowercase,
we cannot do that with entire url in case if for example we are making RESt request to serach engine with case sensitive arguments,

glad that could help you

regards,
Peter Blazejewicz

[rafael.osipov]

Thank you.