Xalan-Java implements the W3C Recommendation 16 November 1999 XSL Transformations (XSLT) Version 1.0.

See:
Description

XSLT_Packages

org.apache.xalan.xslt	The main Xalan-Java package -- facilities for setting up and performing XSL transformations.
org.apache.xalan.xslt.client	Non-visual applet for hosting the Xalan-Java processor.
org.apache.xalan.xslt.extensions	Extension for redirecting transformation ouput to multiple files.
org.apache.xalan.xslt.trace	Xalan-Java debugging interface.

XPATH_Packages

org.apache.xalan.xpath	Infrastructure for processing XPATH expressions
org.apache.xalan.xpath.dtm	Default liaison and XML parser.
org.apache.xalan.xpath.xdom	Liaison for the Xerces XML parser.
org.apache.xalan.xpath.xml	Infrastructure for working with an XML parser.

Xalan-Java implements the W3C Recommendation 16 November 1999 XSL Transformations (XSLT) Version 1.0.

XLST is a stylesheet language for transforming XML documents into other XML documents, HTML documents, or other document types. The language includes the XSL Transformation vocabulary and XPath, a language for addressing parts of an XML document. An XSL stylesheet describes how to transform the tree of nodes in the XML input into another tree of nodes.

Basic procedure for performing transformations:

1. Use one of the XSLTProcessorFactory static getProcessor methods to instantiate an XSLTProcessor.
   
   By default, the XSLTProcessor uses the DTMLiaison and the high-performance DTM (Document Table Model) "pseudo" DOM parser to process the input. If your input or output is a DOM node (rather than a URL, file, or stream), Xalan-Java uses and the Xerces DOM parser.
   
   The XSLT and XPath engines are independent from any given DOM or XML implementation. All parser-dependent calls are funneled through the XMLParserLiaison.
   
   
2. Set up XSLTInputSource objects for the XML input and XSL stylesheet. You can use a file name or URL, character stream, byte stream, or SAX input stream to instantiate an XSLTInputSource object.
   
   If the XML document contains a stylesheet Processing Instruction (PI), you do not need to create a separate XSLTInputSource object for an XSL stylesheet.
   
   Note: For improved performance with a series of transformations, use the XSLTProcessor processStylesheet method to compile the XSL stylesheet. The result is a StylesheetRoot object with its own process() method for performing transformations. Compiling the stylesheet is also useful when you need to get information from the stylesheet before the transformation occurs. You also must compile the stylesheet if you are using the XSLTProcessor as a SAX document handler.
   
   
3. Set up an XSLTResultTarget for the transformation output. You can use a file name or URL, character stream, byte stream, or SAX document handler to instantiate an XSLTResultTarget object.
   
   
4. Use the XSLTProcessor or (if you have compiled the stylesheet) the(@link org.apache.xalan.xslt.StylesheetRoot} process method to perform the transformation.
   
   Xalan-Java is thread-safe for one instance per thread. If you are using the same instance of XSLTProcessor to perform more than one transformation, call the reset method between transformations.

For an introduction to basic usage patterns, see Usage Patterns.