java-util

Helpful Java utilities that are thoroughly tested and available on Maven Central. This library has no dependencies on other libraries for runtime. The.jarfile is 336K and works with JDK 1.8 through JDK 23. The .jar file classes are version 52 (JDK 1.8)

Compatibility

JPMS (Java Platform Module System)

This library is fully compatible with JPMS, commonly known as Java Modules. It includes a module-info.class file that specifies module dependencies and exports.

OSGi

This library also supports OSGi environments. It comes with pre-configured OSGi metadata in the MANIFEST.MF file, ensuring easy integration into any OSGi-based application.

Both of these features ensure that our library can be seamlessly integrated into modular Java applications, providing robust dependency management and encapsulation.

---

To include in your project:

Gradle

implementation 'com.cedarsoftware:java-util:2.18.0'

Maven

<dependency>
  <groupId>com.cedarsoftware</groupId>
  <artifactId>java-util</artifactId>
  <version>2.18.0</version>
</dependency>

---

Included in java-util:

Sets

• CompactSet - A memory-efficient Set implementation that dynamically adapts its internal storage structure based on size:
  • Starts with minimal memory usage for small sets (0-1 elements)
  • Uses a compact array-based storage for medium-sized sets (2 to N elements, where N is configurable)
  • Automatically transitions to a full Set implementation of your choice (HashSet, TreeSet, etc.) for larger sizes
  • Features:
    • Configurable size thresholds for storage transitions
    • Support for ordered (sorted, reverse, insertion) and unordered sets
    • Optional case-insensitive string element comparisons
    • Custom comparator support
    • Memory optimization for single-element sets
    • Compatible with all standard Set operations
  • Ideal for:
    • Applications with many small sets
    • Sets that start small but may grow
    • Scenarios where memory efficiency is crucial
    • Systems needing dynamic set behavior based on size
• CaseInsensitiveSet - A Set that ignores case sensitivity for Strings.
• ConcurrentSet - A thread-safe Set that allows null elements.
• ConcurrentNavigableSetNullSafe - A thread-safe drop-in replacement for ConcurrentSkipListSet that allows null values.

Maps

• CompactMap - A memory-efficient Map implementation that dynamically adapts its internal storage structure based on size:
  • Starts with minimal memory usage for small maps (0-1 entries)
  • Uses a compact array-based storage for medium-sized maps (2 to N entries, where N is configurable)
  • Automatically transitions to a full Map implementation of your choice (HashMap, TreeMap, etc.) for larger sizes
  • Features:
    • Configurable size thresholds for storage transitions
    • Support for ordered (sorted, reverse, insertion) and unordered maps
    • Optional case-insensitive string key comparisons
    • Custom comparator support
    • Memory optimization for single-entry maps
    • Compatible with all standard Map operations
  • Ideal for:
    • Applications with many small maps
    • Maps that start small but may grow
    • Scenarios where memory efficiency is crucial
    • Systems needing dynamic map behavior based on size
• CaseInsensitiveMap - Treats String keys in a case-insensitive manner.
• LRUCache - Thread-safe LRU cache which implements the Map API. Supports "locking" or "threaded" strategy (selectable).
• TTLCache - Thread-safe TTL cache which implements the Map API. Entries older than Time-To-Live will be evicted. Also supports a maxSize (LRU capability).
• TrackingMap - Tracks access patterns to its keys, aiding in performance optimizations.
• ConcurrentHashMapNullSafe - A thread-safe drop-in replacement for ConcurrentHashMap that allows null keys & values.
• ConcurrentNavigableMapNullSafe - A thread-safe drop-in replacement for ConcurrentSkipListMap that allows null keys & values.

Lists

• ConcurrentList - Provides a thread-safe List that can be either an independent or a wrapped instance.

Utilities

• ArrayUtilities - Provides utilities for working with Java arrays [], enhancing array operations.
• ByteUtilities - Offers routines for converting byte[] to hexadecimal character arrays and vice versa, facilitating byte manipulation.
• ClassUtilities - Includes utilities for class-related operations. For example, the method computeInheritanceDistance(source, destination) calculates the number of superclass steps between two classes, returning it as an integer. If no inheritance relationship exists, it returns -1. Distances for primitives and their wrappers are considered as 0, indicating no separation.
• Converter - Facilitates type conversions, e.g., converting String to BigDecimal. Supports a wide range of conversions.
• DateUtilities - Robustly parses date strings with support for various formats and idioms.
• DeepEquals - Deeply compares two object graphs for equivalence, handling cycles and using custom equals() methods where available.
• IOUtilities - Transfer APIs, close/flush APIs, compress/uncompress APIs.
  • FastReader and FastWriter - Provide high-performance alternatives to standard IO classes without synchronization.
  • FastByteArrayInputStream and FastByteArrayOutputStream - Non-synchronized versions of standard Java IO byte array streams.
• EncryptionUtilities - Simplifies the computation of checksums and encryption using common algorithms.
• Executor - Simplifies the execution of operating system commands with methods for output retrieval.
• GraphComparator - Compares two object graphs and provides deltas, which can be applied to synchronize the graphs.
• MathUtilities - Offers handy mathematical operations and algorithms.
• ReflectionUtils - Provides efficient and simplified reflection operations.
• StringUtilities - Contains helpful methods for common String manipulation tasks.
• SystemUtilities - Offers utilities for interacting with the operating system and environment.
• Traverser - Allows generalized actions on all objects within an object graph through a user-defined method.
• UniqueIdGenerator - Generates unique identifiers with embedded timing information, suitable for use in clustered environments.

See changelog.md for revision history.

---

Sponsors

YourKit supports open source projects with its full-featured Java Profiler. YourKit, LLC is the creator of YourKit Java Profiler and YourKit .NET Profiler, innovative and intelligent tools for profiling Java and .NET applications.

Intellij IDEA

---

By: John DeRegnaucourt and Kenny Partlow