package

com.atlassian.jira.util.dbc

This package contains utility classes for performing Design By Contract (DBC) assertions. For example, use Assertions.notNull("myParam", myParam) to check that the value of myParam is not null, and if it is, to throw an IllegalArgumentException.

Other suitable classes here would check Collections types for non-null elements, or to check the types of the contents of collections.

Classes

Assertions Utility class with design by contract checks. 
Null Utility class with checks for nullness. 
NumberAssertions Utility for number assertions