I am new to the development of smart contract using web3j. I am facing issue, while converting Bytes32[] returned from wrapper of contract(.sol) method to array.

I have contract as:

pragma solidity ^0.4.4;
contract Person
    Person[] public people;

    struct Person
        bytes32 firstName;
        bytes32 lastName;


    function addPerson(bytes32 _firstName, bytes32 _lastname) returns (bool success)
        Person memory newPerson;

        newPerson.firstName = _firstName;
        newPerson.lastName = _lastname;

        return true;

    function getPeople() constant returns (bytes32[], bytes32[])
        uint leng = people.length;

        bytes32[] memory first_names = new bytes32[](leng);
        bytes32[] memory last_names = new bytes32[](leng);

        for (uint i = 0; i < people.length; i++ )
            Person memory currentPerson;
            currentPerson = people[i];
            first_names[i] = (currentPerson.firstName);
            last_names[i] = (currentPerson.lastName);

        return (first_names,last_names);

Function from generated java wrapper as:

    public RemoteCall<Tuple2<List<byte[]>, List<byte[]>>> getPeople() {
        final Function function = new Function("getPeople", 
                Arrays.<TypeReference<?>>asList(new TypeReference<DynamicArray<Bytes32>>() {}, new TypeReference<DynamicArray<Bytes32>>() {}));
        return new RemoteCall<Tuple2<List<byte[]>, List<byte[]>>>(
                new Callable<Tuple2<List<byte[]>, List<byte[]>>>() {
                    public Tuple2<List<byte[]>, List<byte[]>> call() throws Exception {
                        List<Type> results = executeCallMultipleValueReturn(function);;
                        return new Tuple2<List<byte[]>, List<byte[]>>(
                                (List<byte[]>) results.get(0).getValue(), 
                                (List<byte[]>) results.get(1).getValue());

In my main function, I am trying access Bytes of Array returned from getPeople method. But I am not note able to converted Bytes of array to string. I am storing tuples values in main method as:

Tuple2<List<byte[]>, List<byte[]>> x = contract.getPeople().send();

I want to convert value, x.getValue1() to string. Can anyone please tell me how to do it.

1 Answer 1


Pass your hex or byte in this method will return you the string..

var hexToUtf8 = function(hex) { if (!isHexStrict(hex)) throw new Error('The parameter "'+ hex +'" must be a valid HEX string.');

var str = "";
var code = 0;
hex = hex.replace(/^0x/i,'');

// remove 00 padding from either side
hex = hex.replace(/^(?:00)*/,'');
hex = hex.split("").reverse().join("");
hex = hex.replace(/^(?:00)*/,'');
hex = hex.split("").reverse().join("");

var l = hex.length;

for (var i=0; i < l; i+=2) {
    code = parseInt(hex.substr(i, 2), 16);
    // if (code !== 0) {
    str += String.fromCharCode(code);
    // }

return utf8.decode(str);


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