Compiling a Stylesheet

The facility to "compile" a stylesheet to a binary disk representation (the CompileStylesheet command and the -c option of net.sf.saxon.Transform) was dropped with effect from Saxon 9.4.

Saxon generates Java bytecode automatically when stylesheets are processed, but the bytecode cannot be saved to disk, because it is integrated with interpreted data structures representing the executable stylesheet.

The performance boost achieved by bytecode generation is variable; 25% is typical. The constructs that benefit the most are those where the expression tree contains many constructs that are relatively cheap in themselves, such as type conversion, comparisons, and arithmetic. This is because the saving from bytecode generation is mainly not in the cost of performing primitive operations, but in the cost of deciding which operations to perform: so the saving is greater where the number of operations is high relative to their average cost.

There are configuration options to suppress bytecode generation (FeatureKeys.GENERATE_BYTE_CODE), to insert debugging logic into the generated bytecode (FeatureKeys.DEBUG_BYTE_CODE), and to display the generated bytecode (FeatureKeys.DISPLAY_BYTE_CODE). See Configuration Features for more information.

A facility for distributing an obfuscated stylesheet is available (this was the main use case for compiled stylesheets, since there were negligible performance benefits). This is described in the next section Packaged Stylesheets.