From the Android developer web link: http://developer.android.com/reference/android/content/Intent.html, you can find that it says "It (Intent) is basically a passive data structure holding an abstract description of an action to be performed." But I don‘t understand what is "passive data structure"?
A passive data structure (opposite of active data structure, or functional data structure) is one that is managed exclusively by external threads. That is to say, it does not have some associated thread which performs operations on it.
Basically, it‘s like a container of information; you create it, set all its information, and it just exists to be accessed by other processes (in Android, Activity objects, usually). Hence, it is not actively being access (so it‘s not "active"), and it is not being operated on (not "functional"), so it should be considered passive.
https://stackoverflow.com/questions/12452930/what-is-passive-data-structure-in-android-java
What is “passive data structure” in Android/Java?
原文：http://www.cnblogs.com/jianglijs/p/7549893.html