Using contract to create Child contracts (web3j Java wrapper)

Question

I have a simple Parent contract that creates child contracts and stores their address.

contract Parent {
    address[] public registry;

    function createChild () public {
        address newChild = address(new Child());
        registry.push(newRecord);
    }
 }

 contract Record {
    string public uid;
 }

Using web3j generated wrappers, I try to call this creation method:

contract.createChild().send();

contract being the Parent instance. However I get this error:

{
  "timestamp": "2019-07-05",
  "status": 500,
  "error": "Internal Server Error",
  "message": "org/bouncycastle/jcajce/provider/digest/Keccak$DigestKeccak",
  "path": "/api/deployRecord"
}

Can anyone tell me why? Or can I achieve this some other way using web3j? It seems like a really simple thing to do :/

Thanks

Answer 1

Not an expert on web3j here, but you are trying to invoke something called contract.createRecord() when the function in the contract is called ...createChild().

The contract itself can't compile because you have a contract, Record, nested in a contract. It should look like:

contract Child {
  // stuff
}

contract Parent {
    address[] public registry;

    function createChild () public { // the function to invoke
        address newChild = address(new Child()); // the contract to create defined above
        registry.push(newRecord);
    }
}

Hope it helps.