Created attachment 1458695 [details] reproducer Description of problem: application server crashes with a StackOverflowError due to a bug in the xerces library (xercesImpl-2.9.1.redhat-6.jar) which is integrated into The issue is well known as XERCESJ-589 (https://issues.apache.org/jira/browse/XERCESJ-589) and arises during validation of XML data containing long strings. Version-Release number of selected component (if applicable): EAP 6.4.20. How reproducible: Always Steps to Reproduce: 1. Deploy attachment in EAP 6.4.x instance 2. Boot up EAP 6.4.x 3. Actual results: EAP logs contains 11:20:17,546 INFO [org.jboss.as.ejb3.deployment.processors.EjbJndiBindingsDeploymentUnitProcessor] (MSC service thread 1-5) JNDI bindings for session bean named XMLValidationTest in deployment unit subdeployment "ejb_pack_1.jar" of deployment "Reproducer.ear" are as follows: java:global/testApp/ejb_pack_1/XMLValidationTest!framework.application.XMLValidationTest java:app/ejb_pack_1/XMLValidationTest!framework.application.XMLValidationTest java:module/XMLValidationTest!framework.application.XMLValidationTest java:global/testApp/ejb_pack_1/XMLValidationTest java:app/ejb_pack_1/XMLValidationTest java:module/XMLValidationTest 11:20:17,806 FATAL [framework.application.XMLValidationTest] (ServerService Thread Pool -- 50) Error: java.lang.StackOverflowError at org.apache.xerces.impl.xpath.regex.REUtil.isHighSurrogate(REUtil.java:40) at org.apache.xerces.impl.xpath.regex.RegularExpression.matchString(RegularExpression.java:1667) at org.apache.xerces.impl.xpath.regex.RegularExpression.matchString(RegularExpression.java:1879) at org.apache.xerces.impl.xpath.regex.RegularExpression.matchString(RegularExpression.java:1905) at org.apache.xerces.impl.xpath.regex.RegularExpression.matchString(RegularExpression.java:1879) at org.apache.xerces.impl.xpath.regex.RegularExpression.matchString(RegularExpression.java:1905) Expected results: Successful validation Additional info: Works in EAP 7.1.3 Initially fixed in EAP 5.2. ref https://issues.jboss.org/browse/JBPAPP-9156