org.web3j.tx.exceptions.ContractCallException: Empty value (0x) returned from contract

Question

Problem: org.web3j.tx.exceptions.ContractCallException: Empty value (0x) returned from contract

The code is as follows....

My java:

String owner = managedWalletLookup.getOwner(contractAddress).send();

This ^ line of code calls this auto-generated Java wrapper:

public RemoteCall<String> getOwner(String wallet) {
    final Function function = new Function(FUNC_GETOWNER,
            Arrays.<Type>asList(new org.web3j.abi.datatypes.Address(wallet)),
            Arrays.<TypeReference<?>>asList(new TypeReference<Address>() {}));
    return executeRemoteCallSingleValueReturn(function, String.class);
}

This is the original solidity, from which the Java wrapper gets generated:

mapping(address => address) public _managedWallets;


function updateManagedWallets(address wallet, address owner) public isOwner {
    _managedWallets[wallet] = owner;
}

function getOwner(address wallet) public view returns (address owner) {
    owner = _managedWallets[wallet];
    return owner;
}

Every time I call updateManagedWallets, I get a successful TransactionReciept, but the getOwner function always generates an error.

Any thoughts?

Answer 1

I have the exact same problem and I managed to make it work just one time using the following call. Now I cannot obtain the value again.

You could also try, or read more about this

String owner = managedWalletLookup.getOwner(contractAddress).sendAsync().get();