So I want to load a wallet and get its balance also sending some funds with the corresponding wallet, here is my code

public class DumpWallet {
public static void main(String[] args) throws Exception {


    Wallet wallet = Wallet.loadFromFile(new File("wallet.dat"));
    System.out.println(wallet.toString());
}
}

Why does it throw these followings error (I am using wallet.dat that created automatically on C:\Users\<username>\AppData\Roaming\Bitcoin\testnet3

Exception in thread "main" org.bitcoinj.wallet.UnreadableWalletException: Could not parse input stream to protobuf
at org.bitcoinj.wallet.WalletProtobufSerializer.readWallet(WalletProtobufSerializer.java:427)
at org.bitcoinj.wallet.WalletProtobufSerializer.readWallet(WalletProtobufSerializer.java:399)
at org.bitcoinj.wallet.Wallet.loadFromFileStream(Wallet.java:1581)
at org.bitcoinj.wallet.Wallet.loadFromFile(Wallet.java:1487)
at org.bitcoinj.examples.DumpWallet.main(DumpWallet.java:33)
Caused by: com.google.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).
    at com.google.protobuf.InvalidProtocolBufferException.invalidTag(InvalidProtocolBufferException.java:89)
    at com.google.protobuf.CodedInputStream.readTag(CodedInputStream.java:158)
    at org.bitcoinj.wallet.Protos$Wallet.<init>(Protos.java:14789)
    at org.bitcoinj.wallet.Protos$Wallet.<init>(Protos.java:14778)
    at org.bitcoinj.wallet.Protos$Wallet$1.parsePartialFrom(Protos.java:14956)
    at org.bitcoinj.wallet.Protos$Wallet$1.parsePartialFrom(Protos.java:1)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:89)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:95)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:49)
    at org.bitcoinj.wallet.Protos$Wallet.parseFrom(Protos.java:15822)
    at org.bitcoinj.wallet.WalletProtobufSerializer.parseToProto(WalletProtobufSerializer.java:606)
    at org.bitcoinj.wallet.WalletProtobufSerializer.readWallet(WalletProtobufSerializer.java:420)
    ... 4 more