Utility class is a kind of conceptual class that includes commonly used methods for the related operations. It groups methods together that have the similar purpose about a specific topic and these methods are static which makes them easy to use.
Examples of ABAP Utility Objects ;
CL_HTTP_UTILITY
CL_BSP_UTILITY
CL_ABAP_CHAR_UTILITIES
CL_ABAP_MEMORY_UTILITIES
CL_ABAP_STRING_UTILITIES
....
For Java ;
java.util.Collections
Wikipedia ;
http://en.wikipedia.org/wiki/Utility_class
