Plugin Help How to set a tag for item?

I create a plugin gun but it in a mode survival so people can create a gun with material and anvil to change name because my gun don't have tag and i target it by name. I hope everyone help me how to set tag for item in bukkit 1.10.2. Thank you so much!!!

 

Code:

      
ItemMeta meta = heldItem.getItemMeta();
        if (meta.hasMetadata("test_fly")) {
            sendError(player, "That item is already a super awesome flying item");
            return;
        }
        Map<String, Object> flyData = new HashMap<String, Object>();
        Date now = new Date();
        flyData.put("created", now.toString());
        flyData.put("uses", 0);
        flyData.put("speed", 2.0);
        meta.setMetadata("test_fly", new PersistentMetadataValue(this, flyData));
        heldItem.setItemMeta(meta);

You can set an ItemMeta being the name or any other property in Meta Data.