Create list item using SharePoint Client Object Model (also get the ID of newly created Item)

function createNewItem(){
         var clientContext = SP.ClientContext.get_current();
         var oList = clientContext.get_web().get_lists().getByTitle(List_Name);  
         var itemCreateInfo = new SP.ListItemCreationInformation();
         this.oListItem = oList.addItem(itemCreateInfo);

         oListItem.set_item('Group', group_value);
         oListItem.update();
         clientContext.load(oListItem);
         clientContext.executeQueryAsync(
                  Function.createDelegate(this, this.onQuerySucceed), 
                  Function.createDelegate(this, this.onQueryFailed));
} // createNewItem method ends.

function onQuerySucceed() {
        var newID =  oListItem.get_id();
}

function  onQueryFailed(){
        alert(‘operation failed’);
}