The system call allows students to examine Android's
process tree and application startup method, which pro-
vide insight into a key system design that drives the entire
Java-based user environment. Java applications are inter-
preted in the Dalvik virtual machine, and are represented in
the OS as processes which are children of a special process
called the zygote. The Dalvik virtual machine starts several
worker threads for each application to handle things like in-
put events and garbage collection. Thus, the process tree of
Android devices shows not only the relationship between the
init process and its children, but also the relationship that
all Java applications have to the zygote and the symmetry
of their component threads.