How to catch exception when creating MongoClient instance

Question

I am using Mongo DB java driver to connect to mongo instance. Below is the code I am using to create the MongoClient instance.

try {
            new MongoCl         


        

Answer 1

It's pretty simple and elegant:

1. Redirect System.err to a file:

   ByteArrayOutputStream file=new ByteArrayOutputStream();
   System.setErr(new PrintStream(file));
   

2. Connect to the server with your MongoClient and your MongoCredentials:

   MongoCredential credenciales=MongoCredential.createCredential("root", "admin", "root".toCharArray());
   MongoClient client = new MongoClient(new ServerAddress("localhost"), Arrays.asList(credenciales));
   

3. Read the error output, which is in the ByteArrayOutputStream object:

   String texto=new String(file.toByteArray());
   

4. Check whether the Autentication failed string is present:

   if (texto.contains("'Authentication failed.'"))
      // do something;
   else
     ...