Java: XML canonicalization

Another option is nu.xom.canonical.Canonicalizer if you're using XOM, or if you don't otherwise have a need for Apache XML Security.

The Canonicalizer class at Apache XML Security project.

Initialize the library.

org.apache.xml.security.Init.init(); 

Convert your XML.

Canonicalizer canon = Canonicalizer.getInstance(Canonicalizer.ALGO_ID_C14N_OMIT_COMMENTS);
byte canonXmlBytes[] = canon.canonicalize(yourXmlBytes);
String canonXmlString = new String(canonXmlBytes);