JsArrayToJava

function findDepth(item) {
    if (Array.isArray(item) == false) return 0;
    if (item.length == 0) return 1;
    return 1 + findDepth(item[0]);
}
function depthToBracket(d) {
    let ret = "";
    for (let i = 1; i <= d; i++) {
        ret += "[]";
    }
    return ret;
}
function doFlat(item, depth, type) {
    if (depth == 0) return item;
    if (item.length === 0) return `new ${type}[]{}`;
    return  `new ${type}${depthToBracket(depth)}{${item.map(i => doFlat(i, depth - 1, type))}}`;
}
function flatter(item, type = "int") {
    const depth = findDepth(item);
    return `${doFlat(item, depth, type)};`;
}

console.log(flatter([1, 2]));
console.log(flatter([]));
console.log(flatter([[1, 2], [3, 4]]));
console.log(flatter([[[], []], [[], []]]));
console.log(flatter([[[], []], [[1], []]]));