Internet issue in blackberry - blackberry

Question

I am developing a blackberry app for sending messages through internet . i have succesfully completed the project, but now i am getting error "to check the net connection even if the net connection is available.
I have closed my http connection .but still the issue persist .
Sometimes it works alright but after somtime it throws the error ".
In one word it is not getting the internet connection .
Please help me.
this is my code
InputStream in=null;
int rc=0;
HttpConnection http=null;
ConnectionFactory factory = new ConnectionFactory();
try{
String u="my url goes here";deviceside=true";
ConnectionDescriptor descriptor = factory.getConnection(u);
http = (HttpConnection)descriptor.getConnection();
in = http.openDataInputStream();
rc = http.getResponseCode();
if (rc != HttpConnection.HTTP_OK) {
Dialog.inform("Please Check The Internet Connection ");
}
int ch;
while ( (ch = in.read())!= -1){
buff3.append( (char) ch);
}
Dialog.inform(" Your Balance Is \n " +buff3.toString() );
buff3.delete(0,buff3.toString().length());
// buff3=new StringBuffer();
//stringItem.setText(" Your Balance Is \n " +buff.toString());
}
catch(Exception o){
Dialog.inform("Please Check The Internet Connection ");
buff3.delete(0,buff3.toString().length());
}
finally
{
try {
if(in != null)
in.close();
if(http != null)
http.close();
buff3.delete(0,buff3.toString().length());
} catch (IOException ex) {
ex.printStackTrace();
}
}