Technically correction for Android app starting

> When Android runs an app, it does so by spawning a new thread which typically starts by mapping a number of VMAs.

When Android runs an app, it forks a new process from the zygote process. zygote contains an already stared Java VM including all the framework java libraries. Since fork() uses Copy-on-Write the parent and child process shared a lot of the memory pages. When the child starts to write to some of these shared pages, page faults occur, because the pages are mapped as read-only.