int npcId = getTemplate().getId();
switch (npcId)
{
case 150:
final L2PcInstance player = killer.getActingPlayer();
if (player != null)
{
final L2Clan clan = player.getClan();
if (clan != null)
{
clan.addReputationScore(10, true); // Change 10 with the reputation points you want to add upon kill monster
}
final L2Summon summon = killer.getSummon();
if (summon != null)
{
return false;
}
player.sendMessage("Your Clan Reputation is increased by 10.");
}
Changed code like that, now it is working without any NPE, thank you all ^-^
Gries's post in Code Npe was marked as the answer