user3408: I try to open the bitcoin-qt wallet with bitcoinj, I write this code:
private static final File WALLET_FILE = new File("C:\\Users\\Bapt\\AppData\\Roaming\\Bitcoin\\wallet.dat");

public static void main(String[] args) {
    NetworkParameters networkParameters = NetworkParameters.prodNet();

    Wallet wallet;
    try {
        wallet = Wallet.loadFromFile(WALLET_FILE);
    } catch (IOException e) {
        System.out.println("Couldn't open wallet: " + e);
        return;
    }

    System.out.println("Balance: " + wallet.getBalance());
}

But I have an error: 
Couldn't open wallet: com.google.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).

So I have two questions:

Is is possible to do what I want ?
If yes, what do you think could happen here ?

Thanks for your answer.

user859: BitcoinJ has its own wallet format, and official bitcoin client its own.

3408: <p>I try to open the bitcoin-qt wallet with bitcoinj, I write this code:</p>

<pre><code>private static final File WALLET_FILE = new File("C:\\Users\\Bapt\\AppData\\Roaming\\Bitcoin\\wallet.dat");

public static void main(String[] args) {
    NetworkParameters networkParameters = NetworkParameters.prodNet();

    Wallet wallet;
    try {
        wallet = Wallet.loadFromFile(WALLET_FILE);
    } catch (IOException e) {
        System.out.println("Couldn't open wallet: " + e);
        return;
    }

    System.out.println("Balance: " + wallet.getBalance());
}
</code></pre>

<p>But I have an error: </p>

<pre><code>Couldn't open wallet: com.google.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).
</code></pre>

<p>So I have two questions:</p>

<ul>
<li>Is is possible to do what I want ?</li>
<li>If yes, what do you think could happen here ?</li>
</ul>

<p>Thanks for your answer.</p>
 859: <p>BitcoinJ has its own wallet format, and official bitcoin client its own.</p>
