Commons Lang
Lang aims to provide:
Comprehensive String handling utilities
Enumerated types (pre JDK 1.5)
Nested exceptions (pre JDK 1.4)
Builders to create hashCode, equals, toString and compareTo methods
Utilities for Object, Date and Numbers
The Javadoc of the latest version (2.1) is
available.
The Javadoc of the CVS version (development) is
available.
Development plan for 2.2
Bug fixes
VariableFormatter/interpolator -
18962
Other ideas
21663 [lang] Add support in ToStringStyle for DateFormat. - Grows quickly into commons-convert
27643 [lang][patch] ClassUtils.newInstance method - Seems unnecessary
29149 [lang] StringEscapeUtils.unescapeHtml() doesn't handle an empty entity - Empty entity is in fact illegal HTML, so need to decide if we should ignore. Current behaviour seems acceptable as we're not in the work with bad HTML market.
26659 [lang] add method to DateUtils to get the distance between 2 dates - Mainly replicated by DurationFormatUtils, or non-obvious
29692 [lang] String indentation feature request - Needs design as a non-simple problem
22172 [lang] DateUtils.parseCVS behavior parsing "h:mm z" - Moved to sandbox
26297 [lang] BitSetUtils class, toIndexArray and fromIndexArray
21333 Add TimeoutController - Class in HttpClient. Leaving til 3.0 as not much movement on it
30674 Support HttpClient's DateParser class - This is basically a Date parseDate(String dateValue, String[] dateFormats) method. LocaleUtils - including toLocale(String,String)
CloneUtils - multiple ways to clone an object
Articles
This article
http://www.devx.com/Java/Article/29392/0/page/6 discusses some of the interesting classes in Commons Lang with real world examples.