@OneToMany(targetEntity = Friends.class, mappedBy = "firstUser")
    @Cascade({org.hibernate.annotations.CascadeType.ALL, org.hibernate.annotations.CascadeType.DELETE_ORPHAN})
    @LazyCollection(LazyCollectionOption.EXTRA)
    @Cache(usage = CacheConcurrencyStrategy.TRANSACTIONAL)
    @OptimisticLock(excluded = true)   
    public List<Friends> getFriends() {
        return friends;
    }

List<Friends> friends = parent.getFriends(); //select just the IDs of 'friends'
friends.size(); //no SELECTs -
friends.get(0); //select a single 'Friends' entitity

User userBob = session.get(bobId); //caches one User entity

Collection<Friends> allFriends = userBob.getFriends();
//returns a proxy collection; creates a single Collection cache entry with 3000 IDs (need this cached to avoid repeat query)

//count all of bob's friends: issue sql like "select * from friends where firstUserId=bobId" - problem is this results in initialization (and caching) or 3000 Friends entities. need to avoid that
int totalFriends = allFriends.size();

//find out who's online in general
Collection<Long> onlineUserIDs = systemService.getOnlineUserIDs(); //another service that keeps tracks IDs of all users currently online

//now I want to filter allFriends using onlineUserIDs and only load and cache Friends and User entities for Bob's onlineFriends
Set<Friends> onlineFriends = session.createFilter(allFriends, " where this.secondUser.id in: " onlineUserIDs); //last arg is pseudo code

//now retrieve and cache needed info for the 10 online friends only
List<User> onlineFriendUsers = new ArrayList<User>(onlineFriends.size());
for(Friends f : onlineFriends)
{
User onlineUser = f.getSecondUser(); //fetch, cache, and initialize a single Friends entity; return User proxy
String userName = onlineUser.getUserName(); //fetch, cache, and initialize a single User entity
onlineFriendUsers.add(onlineUser);
}

//at the end of all this we should only have:
//11 Users in entity cache (bob + 10 online friends)
//1 user.friends entry in collection cache (with 3000 IDs)
//10 Friend entities in entity cache (one for each online friend of Bob)

return onlineFriendUsers;

Create Table: CREATE TABLE `friends` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `hibernateVersion` int(11) NOT NULL,
  `creationDate` datetime DEFAULT NULL,
  `firstUserId` bigint(20) NOT NULL,
  `secondUserId` bigint(20) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `firstUserId` (`firstUserId`,`secondUserId`),
  KEY `FKDC3B499515152FBC` (`firstUserId`),
  KEY `FKDC3B499528AE3E80` (`secondUserId`),
  CONSTRAINT `FKDC3B499515152FBC` FOREIGN KEY (`firstUserId`) REFERENCES `users` (`id`),
  CONSTRAINT `FKDC3B499528AE3E80` FOREIGN KEY (`secondUserId`) REFERENCES `users` (`id`)
)

Create Table: CREATE TABLE `users` (
  `id` bigint(20) NOT NULL,
  `hibernateVersion` int(11) NOT NULL,
  `userName` varchar(255) NOT NULL
)

    //User.friends collection:
    @OneToMany(targetEntity = Friends.class, mappedBy = "firstUser")
    @Cascade({org.hibernate.annotations.CascadeType.ALL, org.hibernate.annotations.CascadeType.DELETE_ORPHAN})
    @LazyCollection(LazyCollectionOption.EXTRA)
    @Cache(usage = CacheConcurrencyStrategy.TRANSACTIONAL)
    @OptimisticLock(excluded = true)   
    public List<Friends> getFriends() {
        return friends;
    }

<?xml version="1.0" encoding="UTF-8"?>
<server>
    <mbean code="org.jboss.cache.jmx.CacheJmxWrapper" name="jboss.cache:service=TreeCache">
        <depends>jboss:service=Naming</depends>
        <depends>jboss:service=TransactionManager</depends>
        <attribute name="TransactionManagerLookupClass">org.jboss.cache.transaction.GenericTransactionManagerLookup</attribute>
        <attribute name="NodeLockingScheme">PESSIMISTIC</attribute>
        <attribute name="IsolationLevel">REPEATABLE_READ</attribute>
        <attribute name="LockParentForChildInsertRemove">true</attribute>
        <attribute name="CacheMode">INVALIDATION_ASYNC</attribute>
        <attribute name="ClusterName">OIX-Cluster</attribute>
        <attribute name="ClusterConfig">
            <config>
                <UDP mcast_addr="224.0.0.251" mcast_port="4886" ip_ttl="64" ip_mcast="true" mcast_send_buf_size="150000"
                    mcast_recv_buf_size="80000" ucast_send_buf_size="150000" ucast_recv_buf_size="80000" loopback="false"
                    enable_bundling="true" />
                <PING timeout="2000" num_initial_members="3" />
                <MERGE2 min_interval="10000" max_interval="20000" />
                <FD shun="true" />
                <FD_SOCK />
                <VERIFY_SUSPECT timeout="1500" />
                <pbcast.NAKACK gc_lag="50" retransmit_timeout="600,1200,2400,4800" />
                <UNICAST timeout="600,1200,2400,4800" />
                <pbcast.STABLE desired_avg_gossip="400000" />
                <FC max_credits="2000000" min_threshold="0.10" />
                <FRAG2 frag_size="8192" />
                <pbcast.GMS join_timeout="5000" shun="true" print_local_addr="true" />
                <pbcast.STATE_TRANSFER />
            </config>
        </attribute>
        <attribute name="StateRetrievalTimeout">20000</attribute>
        <attribute name="SyncReplTimeout">20000</attribute>
        <attribute name="LockAcquisitionTimeout">15000</attribute>
        <attribute name="ShutdownHookBehavior">DEFAULT</attribute>
        <attribute name="UseLazyDeserialization">true</attribute>
    </mbean>
</server>