Rarely available and hard-to-write Java utilities, written correctly, and thoroughly tested

To include in your project:

<dependency>
  <groupId>com.cedarsoftware</groupId>
  <artifactId>java-util</artifactId>
  <version>1.9.1</version>
</dependency>

<dependency>
  <groupId>com.cedarsoftware</groupId>
  <artifactId>json-io</artifactId>
  <version>2.5.1</version>
</dependency>

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Also, check out json-io at https://github.com/jdereg/json-io

Including in java-util:

• ArrayUtilities - Useful utilities for working with Java's arrays [ ]
• ByteUtilities - Useful routines for converting byte[] to HEX character [] and visa-versa.
• CaseInsensitiveMap - When Strings are used as keys, they are compared without case. Can be used as regular Map with any Java object as keys, just specially handles Strings.
• CaseInsensitiveSet - Set implementation that ignores String case for contains() calls, yet can have any object added to it (does not limit you to adding only Strings to it).
• DateUtilities - Robust date String parser that handles date/time, date, time, time/date, string name months or numeric months, skips comma, etc. English month names only (plus common month name abbreviations), time with/without seconds or milliseconds, y/m/d and m/d/y ordering as well.
• DeepEquals - Compare two object graphs and return 'true' if they are equivalent, 'false' otherwise. This will handle cycles in the graph, and will call an equals() method on an object if it has one, otherwise it will do a field-by-field equivalency check for non-transient fields.
• EncryptionUtilities - Makes it easy to compute MD5 checksums for Strings, byte[], as well as making it easy to AES-128 encrypt Strings and byte[]'s.
• IOUtilities - Handy methods for simplifying I/O including such niceties as properly setting up the input stream for HttpUrlConnections based on their specified encoding. Single line .close() method that handles exceptions for you.
• MathUtilities - Handy mathematical alrogithms to make your code smaller. For example, minimum of array of values.
• ReflectionUtils - Simple one-liners for many common reflection tasks.
• SafeSimpleDateFormat - Instances of this class can be stored as member variables and resued, without any worry about thread safety. Fixing the problems with the JDK's SimpleDateFormat and thread safety (no reentrancy support).
• StringUtilities - Helpful methods that make simple work of common String related tasks.
• SystemUtilities - A Helpful utility methods for working with external entities like the OS, environment variables, and system properties.
• Traverser - Pass any Java object to this Utility class, it will call your passed in anonymous method for each object it encounters while traversing the complete graph. It handles cycles within the graph. Permits you to perform generalized actions on all objects within an object graph.
• UniqueIdGenerator - Generates a Java long unique id, that is unique across server in a cluster, never hands out the same value, has massive entropy, and runs very quickly.
• UrlUtitilies - Fetch cookies from headers, getUrlConnections(), HTTP Response error handler, and more.
• UrlInvocationHandler, SessionAwareInvocationHandler, CookieAwareInvocationHandler - Use to easily communicate with RESTful JSON servers, especially ones that implement a Java interface that you have access to.

Version History

• 1.9.1
• Floating-point allow difference by epsilon value (currently hard-coded on DeepEquals. Will likely be optional parameter in future version).
• 1.9.0
• MathUtilities added. Currently, variable length minimum(arg0, arg1, ... argn) and maximum() functions added. Available for long, double, BigInteger, and BigDecimal. These cover the smaller types.
• CaseInsensitiveMap and CaseInsensitiveSet keySet() and entrySet() are faster as they do not make a copy of the entries. Internally, CaseInsensitiveString caches it's hash, speeding up repeated access.
• StringUtilities levenshtein() and damerauLevenshtein() added to compute edit length. See Wikipedia for understand of the difference. Currently recommend using levenshtein() as it uses less memory.
• The Set returned from the CaseInsensitiveMap.entrySet() now contains mutuable entry's (value-side). It had been using an immutable entry, which disallowed modification of the value-side during entry walk.
• 1.8.4
• UrlUtilities, fixed issue where the default settings for the connection were changed, not the settings on the actual connection.
• 1.8.3
• ReflectionUtilities has new getClassAnnotation(classToCheck, annotation) API which will return the annotation if it exists within the classes super class hierarchy or interface hierachy. Similarly, the getMethodAnnotation() API does the same thing for method annotations (allow inheritance - class or interface).
• 1.8.2
• CaseInsensitiveMap methods keySet() and entrySet() return Sets that are identical to how the JDK returns 'view' Sets on the underlying storage. This means that all operations, besides add() and addAll(), are supported.
• CaseInsensitiveMap.keySet() returns a Set that is case insensitive (not a CaseInsensitiveSet, just a Set that ignores case). Iterating this Set properly returns each originally stored item.
• 1.8.1
• Fixed CaseInsensitiveMap() removeAll() was not removing when accessed via .keySet()
• 1.8.0
• Added DateUtilities. See description above.
• 1.7.4
• Added "res" protocol (resource) to UrlUtilities to allow files from classpath to easily be loaded. Useful for testing.
• 1.7.2
• UrlUtilities.getContentFromUrl / getContentFromUrlAsString - removed hard-coded proxy server name
• 1.7.1
• UrlUtilities.getContentFromUrl / getContentFromUrlAsString - allow content to be fetched as String or binary (byte[]).
• 1.7.0
• SystemUtilities added. New API to fetch value from environment or System property
• UniqueIdGenerator - checks for environment variable (or System property) JAVA_UTIL_CLUSTERID (0-99). Will use this if set, otherwise last IP octet mod 100.
• 1.6.1
• Added: UrlUtilities.getContentFromUrl();
• 1.6.0
• Added CaseInsensitiveSet.
• 1.5.0
• Fixed: CaseInsensitiveMap's iterator.remove() method, it did not remove items.
• Fixed: CaseInsensitiveMap's equals() method, it required case to match on keys.
• 1.4.0
• Initial version

By: John DeRegnaucourt and Ken Partlow