Hamcrest API and Utility Classes 
Package Description
org.hamcrest
The stable API defining Matcher and its associated interfaces and classes.
Matcher Library 
Package Description
org.hamcrest.beans
Matchers of Java Bean properties and their values.
org.hamcrest.collection
Matchers of arrays and collections.
org.hamcrest.core
Fundamental matchers of objects and values, and composite matchers.
org.hamcrest.internal  
org.hamcrest.number
Matchers that perform numeric comparisons.
org.hamcrest.object
Matchers that inspect objects and classes.
org.hamcrest.text
Matchers that perform text comparisons.
org.hamcrest.xml
Matchers of XML documents.