java.lang.NoClassDefFoundError: org/apache/oro/text/perl/Perl5Util

問題：
使用org.apache.commons.validator.GenericValidator.matchRegexp，發生下列錯誤
Exception in thread "main" java.lang.NoClassDefFoundError: org.apache.oro.text.perl.Perl5Util at org.apache.commons.validator.GenericValidator.matchRegexp(GenericValidator.java:65) at com.fesc.bot.batch.BatchJob.downloadFiles(Unknown Source) at com.fesc.bot.batch.FD903C.exec(Unknown Source) at com.fesc.bot.batch.FD903C.main(Unknown Source) Caused by: java.lang.ClassNotFoundException: org.apache.oro.text.perl.Perl5Util at java.net.URLClassLoader.findClass(URLClassLoader.java:434) at java.lang.ClassLoader.loadClassHelper(ClassLoader.java:665) at java.lang.ClassLoader.loadClass(ClassLoader.java:644) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:358) at java.lang.ClassLoader.loadClass(ClassLoader.java:627) ... 4 more 解決：
由錯誤訊息判斷應該缺少oro project的jar
連到ORO official site，卻發現As of 2010-09-01, the ORO project is retired.

改到common-validator official site，下載最新版本的jar，重新執行程式測試，確認錯誤不會發生。