Replace uses of StringBuffer with StringBuilder.

[turbanoff]

StringBuffer is a legacy synchronized class. StringBuilder is a direct replacement to StringBuffer which generally have better performance. It's quite important for performance in fresh versions of Java which disabled/removed biased locking.

mvn verify

[INFO] Reactor Summary for xalan-j 2.7.3:
[INFO]
[INFO] xalan-j ............................................ SUCCESS [  7.420 s]
[INFO] @xsl.usage taglet JDK9+ ............................ SUCCESS [  2.443 s]
[INFO] Apache XML Serializer .............................. SUCCESS [  8.457 s]
[INFO] Apache Xalan-Java .................................. SUCCESS [ 13.493 s]
[INFO] Apache Xalan-Java Samples .......................... SUCCESS [  1.630 s]
[INFO] Apache Xalan-Java Servlet Sample ................... SUCCESS [  1.972 s]
[INFO] Apache Xalan-Java Applet Sample .................... SUCCESS [  1.223 s]
[INFO] Apache Xalan-Java Brazil Sample .................... SUCCESS [  1.036 s]
[INFO] Apache Xalan-Java XSLTC EJB sample ................. SUCCESS [  1.127 s]
[INFO] Apache Xalan-Java Compiled Servlet Sample .......... SUCCESS [  1.062 s]
[INFO] distribution ....................................... SUCCESS [  3.989 s]
[INFO] integration-tests .................................. SUCCESS [ 10.612 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  54.606 s
[INFO] Finished at: 2024-11-26T10:03:43+03:00