# Introduction

Schema processing is available only with the schema-aware version of the product, Saxon-SA, available from http://www.saxonica.com/.

Saxon can be used as a free-standing schema processor in its own right, either from the command line or from a Java application. In addition, Saxon can be used as a schema-aware XSLT processor or as a schema-aware XQuery processor.

Saxon, from release 8.0 onwards, comes in two versions: a basic version and a schema-aware version. These correspond to different conformance levels defined in the XSLT and XQuery specifications. The basic Saxon product is open source software available free of charge from http://saxon.sf.net/. The schema-aware version known as Saxon-SA, is a commercial product available from Saxonica Limited.

Saxon-SA supports the schema validation APIs in JAXP 1.3. It therefore requires that JAXP 1.3 be installed and present on the classpath. JAXP 1.3 is a standard part of JDK 1.5 (also known as J2SE 5.0) and can be installed as a free-standing component under JDK 1.4.

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