# Package org.apache.commons.lang

Provides highly reusable static utility methods, chiefly concerned with adding value to the `java.lang` classes.

Since:
  1.0

  Most of these classes are immutable and thus thread-safe. However Charset is not currently guaranteed thread-safe under all circumstances.

- Class Summary
  Class | Description
  --- | ---
  ArrayUtils | Operations on arrays, primitive arrays (like `int[]`) and primitive wrapper arrays (like `Integer[]`).
  BitField | Operations on bit-mapped fields.
  BooleanUtils | Operations on boolean primitives and Boolean objects.
  CharEncoding | Character encoding names required of every implementation of the Java platform.
  CharRange | A contiguous range of characters, optionally negated.
  CharSet | A set of characters.
  CharSetUtils | Operations on `CharSet`s.
  CharUtils | Operations on char primitives and Character objects.
  ClassUtils | Operates on classes without using reflection.
  LocaleUtils | Operations to assist when working with a `Locale`.
  NumberRange | Deprecated. Use one of the Range classes in org.apache.commons.lang.math.
  NumberUtils | Deprecated. Moved to org.apache.commons.lang.math.
  ObjectUtils | Operations on `Object`.
  ObjectUtils.Null | Class used as a null placeholder where `null` has another meaning.
  RandomStringUtils | Operations for random `String`s.
  SerializationUtils | Assists with the serialization process and performs additional functionality based on serialization.
  StringEscapeUtils | Escapes and unescapes `String`s for Java, Java Script, HTML, XML, and SQL.
  StringUtils | Operations on `String` that are `null` safe.
  SystemUtils | Helpers for `java.lang.System`.
  Validate | This class assists in validating arguments.
  WordUtils | Operations on Strings that contain words.

- Exception Summary
  Exception | Description
  --- | ---
  IllegalClassException | Thrown when an object is an instance of an unexpected type (a class or interface).
  IncompleteArgumentException | Thrown to indicate an incomplete argument to a method.
  NotImplementedException | Thrown to indicate that a block of code has not been implemented.
  NullArgumentException | Thrown to indicate that an argument was `null` and should not have been.
  SerializationException | Exception thrown when the Serialization process fails.
  UnhandledException | Thrown when it is impossible or undesirable to consume or throw a checked exception.