Deadlock can be avoided by using other methods for achieving mutual exclusion instead of locks.

Deadlock can occur when two threads try to acquire the same locks in different order.

Deadlock can be prevented by ensuring that there is a unique order in which locks (or other resources held like locks) are taken.

When a thread returns from conditional suspension (e.g. after a call to wait()), it can safely assume that the condition it was waiting for is now true.

Locks prevent the OS scheduler from performing a context switch during a critical region.

A thread can acquire more than one lock simultaneously.