Error when deploying on JBoss AS 7.1 - jboss7.x

Question

I am having a problem with deploying my application on JBoss AS 7.1. Here is what happened, we have a project that has been build on JDK 1.4 currently running on JRun 4. We are migrating the project to JDK 1.7 and deploy on JBoss AS 7.1.1.
Made required changes to the project compile in eclipse using JDK 1.7 like "enum", changed implementation of Log4j, etc. However the current project heavily relies on jaxb ver 1.0 implementation (which we would make changes over a period of time to the latest jaxb version and convert the project to web services).
However when I try to deploy the same project in JBoss I get an error as below, any help to get this resolved would be really appreciated.
12:39:55,710 INFO [org.jboss.as.server.deployment] (MSC service thread 1-5) JBAS015876: Starting deployment of "presto.war"
12:40:00,590 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/xerces-1.2.3.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,591 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/xalan-2.0.0.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,593 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/xalanj1compat.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,595 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/batik.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,596 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/jimi-1.0.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,598 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/logkit-1.0b4.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,599 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry lib/avalon-framework-4.0.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/fop.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,611 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry jaxp.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/xalan.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,612 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry crimson.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/xalan.jar" does not point to a valid jar for a Class-Path reference.
12:40:00,617 WARN [org.jboss.as.server.deployment] (MSC service thread 1-5) Class Path entry sax.jar in "/C:/jboss-as-7.1.1.Final/standalone/deployments/presto.war/WEB-INF/lib/xt.jar" does not point to a valid jar for a Class-Path reference.
12:40:01,495 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-8) MSC00001: Failed to start service jboss.deployment.unit."presto.war".POST_MODULE: org.jboss.msc.service.StartException in service jboss.deployment.unit."presto.war".POST_MODULE: Failed to process phase POST_MODULE of deployment "presto.war"
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:119) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_51]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_51]
at java.lang.Thread.run(Thread.java:744) [rt.jar:1.7.0_51]
Caused by: java.lang.RuntimeException: Error getting reflective information for class org.apache.taglibs.xtags.xslt.XalanStyleTag with ClassLoader ModuleClassLoader for Module "deployment.presto.war:main" from Service Module Loader
at org.jboss.as.server.deployment.reflect.DeploymentReflectionIndex.getClassIndex(DeploymentReflectionIndex.java:70) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.ee.metadata.MethodAnnotationAggregator.runtimeAnnotationInformation(MethodAnnotationAggregator.java:58)
at org.jboss.as.ee.component.deployers.InterceptorAnnotationProcessor.handleAnnotations(InterceptorAnnotationProcessor.java:85)
at org.jboss.as.ee.component.deployers.InterceptorAnnotationProcessor.processComponentConfig(InterceptorAnnotationProcessor.java:70)
at org.jboss.as.ee.component.deployers.InterceptorAnnotationProcessor.deploy(InterceptorAnnotationProcessor.java:55)
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:113) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
... 5 more
Caused by: java.lang.NoClassDefFoundError: Lorg/apache/xalan/xslt/XSLTResultTarget;
at java.lang.Class.getDeclaredFields0(Native Method) [rt.jar:1.7.0_51]
at java.lang.Class.privateGetDeclaredFields(Class.java:2397) [rt.jar:1.7.0_51]
at java.lang.Class.getDeclaredFields(Class.java:1806) [rt.jar:1.7.0_51]
at org.jboss.as.server.deployment.reflect.ClassReflectionIndex.<init>(ClassReflectionIndex.java:57) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.server.deployment.reflect.DeploymentReflectionIndex.getClassIndex(DeploymentReflectionIndex.java:66) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
... 10 more
Caused by: java.lang.ClassNotFoundException: org.apache.xalan.xslt.XSLTResultTarget from [Module "deployment.presto.war:main" from Service Module Loader]
at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:190) [jboss-modules.jar:1.1.1.GA]
at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468) [jboss-modules.jar:1.1.1.GA]
at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456) [jboss-modules.jar:1.1.1.GA]
at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398) [jboss-modules.jar:1.1.1.GA]
at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120) [jboss-modules.jar:1.1.1.GA]
... 15 more

Answer 1

From the error stack you can see that:
Caused by: java.lang.ClassNotFoundException: org.apache.xalan.xslt.XSLTResultTarget from [Module "deployment.presto.war:main" from Service Module Loader]
So the class jar file getting loaded is from default JBOSS Modules and clearly the xalan.jar that comes with the JBoss 7(jboss-as-7.1.1.Final\modules\org\apache\xalan\main) does not contain that that class:
You need to either start using the jar file that your application refers to by replacing it with this jar(which is not reccomended) or use jboss-deployment-structure.xml to do so. This link could help you to decide what works best for you