XStream is a simple library to serialize objects to XML and back again.

Features

• Ease of use. A high level facade is supplied that simplifies common use cases.
• No mappings required. Most objects can be serialized without need for specifying mappings.
• Performance. Speed and low memory footprint are a crucial part of the design, making it suitable for large object graphs or systems with high message throughput.
• Clean XML. No information is duplicated that can be obtained via reflection. This results in XML that is easier to read for humans and more compact than native Java serialization.
• Requires no modifications to objects. Serializes internal fields, including private and final. Supports non-public and inner classes. Classes are not required to have default constructor.
• Full object graph support. Duplicate references encountered in the object-model will be maintained. Supports circular references.
• Integrates with other XML APIs. By implementing an interface, XStream can serialize directly to/from any tree structure (not just XML).
• Customizable conversion strategies. Strategies can be registered allowing customization of how particular types are represented as XML.
• Security framework. Fine-control about the unmarshalled types to prevent security issues with manipulated input.
• Error messages. When an exception occurs due to malformed XML, detailed diagnostics are provided to help isolate and fix the problem.
• Alternative output format. The modular design allows other output formats. XStream ships currently with JSON support and morphing.

Typical Uses

• Transport
• Persistence
• Configuration
• Unit Tests

Known Limitations

If using the enhanced mode, XStream can re-instantiate classes that do not have a default constructor. However, if using a different JVM like an old JRockit version, a JDK 1.4 or you have restrictions because of a SecurityManager, a default constructor is required.

The enhanced mode is also necessary to restore final fields for any JDK < 1.5. This implies deserialization of instances of an inner class.

Auto-detection of annotations may cause race conditions. Preprocessing annotations is safe though.

Tutorials

• Two Minute Tutorial
• Alias Tutorial
• Annotations Tutorial
• Converter Tutorial
• Object Streams Tutorial
• Persistence API Tutorial
• JSON Tutorial