Items dissaperaring after taking them out of a chest

Hey,

I've got a strange problem with Chests :\
I use this code to safe the Location and the Items containing in the chest in two ArrayLists (SavedLocations and SavedItemStacks):

Code:java

public void onPlayerInteract(PlayerInteractEvent event) {
    //some If's here
    ItemStack[] i = ((Chest) event.getClickedBlock().getState()).getInventory().getContents();
    Location l = event.getClickedBlock().getState().getLocation();
    if (!(plugin.SavedLocations.contains(l))) {
            plugin.SavedLocations.add(l);
            plugin.SavedItemStacks.add(i);
    }
}
    }

And then I use this code to set the Inventory of the Chest which was opened to the Inventory which was safed by using this code:

Code:java

for (int count = 0; count < plugin.SavedLocations.size(); count++) {
    Location l = plugin.SavedLocations.get(count);
    World world = l.getWorld();
    BlockState b = world.getBlockAt(l).getState();
    if (b instanceof Chest) {
            Chest chest = (Chest) b;
            ItemStack[] stacks = plugin.SavedItemStacks.get(count);
            chest.getInventory().setContents(stacks);                                 
    }
}

This works really fine, no errors in the console, the items are in the chest and I can take them, but if i want to do anything with them (like attacking a player or destroying a block), they dissapear from my inventory. The items which was in the chest, before restoring it, worked fine, but after restoring the chest, this happends to all of the items of the chest and I really don't know why.

Has anyone an idea how I can solve this problem?

Greets from Germany
Luis