This document discusses process synchronization. It defines process synchronization as sharing system resources by processes to minimize inconsistent data. There are two types of processes: independent processes where execution of one does not affect others, and cooperative processes where execution of one can impact others. The critical section is a code segment accessed by multiple processes that needs synchronization to prevent inconsistent updates. Solutions to the critical section problem ensure mutual exclusion, progress, and bounded waiting. The document provides an example Java program to demonstrate the need for synchronization when multiple threads access a shared resource.