What are the most important optimizations in Java code on Android?
<p><br>
I am just starting out programming on Android.  </p>

<p>What is the most computationally expensive Java constructs to avoid when programming an Android App?  </p>

<p>Of cause every algorithm costs instructions, but what about use of Method calls, Object references, Interfaces, Collections and such? What do I need to avoid, and what is "cheap" when I'm programming for speed?</p>
