The Java platform was designed to support concurrent programming, with basic concurrency support in the Java programming language and the Java class libraries. How often do we think about concurrency while writing new code or while doing a code review with the team? A small bug could lead to endless hours of debugging applications for a production issue that is not easy to reproduce locally.
Why do we need concurrent programming? We are in the age where we work with machines that are equipped with multi-core CPUs. The code you deliver should be optimized to run on such machines, utilizing the hardware to its fullest. While designing a concurrent system, we should not interfere with other processes running on the CPU. We want our application to run in its own black box without impacting other processes. These days we have multicore CPUs that can easily handle this but how was this done back in the days when the single-core was used?