Bukkit

import ru.endlesscode.rpginventory.api.InventoryAPI; // for inventory
import ru.endlesscode.rpginventory.api.PetAPI; // for pets

// Give all passive items equipped on player (like a rings, gloves, artifacts etc.)
List<ItemStack> passiveItems = InventoryAPI.getPassiveItems(player); 

// Give all active items (mostly weapons)
List<ItemStack> activeItems = InventoryAPI.getActiveItems(player);

@EventHandler
public void onInventoryOpen(InventoryOpenEvent event) {
    if (InventoryAPI.isRPGInventory(event.getInventory())) {
        // Smth...
    }
}

// Give pet object with all stats and other information
Pet pet = PetAPI.getPet(player);

// Give pet summoning item
ItemStack pet = PetAPI.getPetItem(player);
// or pet.getSpawnItem();

@EventHandler
public void onPetEquip(PetEquipEvent event) {
    Player player = event.getPlayer();
    ItemStack summoningItem = event.getPetItem();
}

@EventHandler
public void onPetUnequip(PetUnequipEvent event) {
    Player player = event.getPlayer();
}