What is a deadlock and how can it be prevented?

A deadlock occurs when two or more processes are blocked forever, each waiting for the other to release a resource. This happens when four conditions are met: mutual exclusion, hold and wait, no preemption, and circular wait. To prevent deadlocks, we can enforce a strict ordering on resource acquisition to eliminate circular waits. Alternatively, we can use timeout mechanisms or allow resource preemption. At Flipkart, preventing deadlocks ensures transaction processing remains smooth even under heavy load.