05. Main vs Background Threads 3

The Android system is capable of running more than one thread at the same time, so that two or more sets of tasks can be processed independent of each other. If there are many threads that need to be run, Android also prioritizes which ones will run at what time and for how long.

A thread also knows how to save its place. It records the values of all variables, and remembers what series of function calls resulted in it getting to the instruction it's currently executing: everything it needs to be able to pick up its work again.

The goal of building any multithreaded application is to run two or more processes at the same time. Modern programming languages and CPUs are designed to take advantage of multithreading, and building apps on the Android platform is no different!

For a more advanced discussion, see this Processes and Threads article.

There's another developer guide on the topic of keeping your app responsive.