9.4. Explicit Pessimistic Locking Example

The following is an example of explicit pessimistic locking that depicts a transaction that runs on one of the cache nodes:
tx.begin()
cache.lock(K)           
cache.put(K,V5)         
tx.commit()             

When the line cache.lock(K) executes, a cluster-wide lock is acquired on K.
When the line cache.put(K,V5) executes, it guarantees success.
When the line tx.commit() executes, the locks held for this process are released.