Java.lang.LinkageError: violation of bootloader restriction: when resolving the "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor method

Question

The JSF web application is trying to retrieve a resource from the Java EE web service. The JSF web application is working fine. Since I added the Http client source to retrieve the web service resources, the JBoss instance states:

15:29:47,689 SEVERE [javax.enterprise.resource.webcontainer.jsf.application] (http--0.0.0.0-443-1) Error Rendering View[/index.xhtml]: javax.el.ELException: /surfaceParts/sideBarLeft.xhtml @14,79 value="#{categories.cats}": java.lang.LinkageError: loader constraint violation: when resolving method "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, at/fhj/ase/ssl/SSLClientHelper, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for resolved class, org/jboss/resteasy/client/core/executors/ApacheHttpClient4Executor, have different Class objects for the type xecutors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V used in the signature at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114) [jsf-impl-2.1.7-jbossorg-2.jar:] at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIData.getValue(UIData.java:731) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIData.getDataModel(UIData.java:1798) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIData.setRowIndex(UIData.java:473) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81) [jsf-impl-2.1.7-jbossorg-2.jar:] at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIData.encodeBegin(UIData.java:1118) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1777) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.render.Renderer.encodeChildren(Renderer.java:168) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402) [jsf-impl-2.1.7-jbossorg-2.jar:] at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:125) [jsf-impl-2.1.7-jbossorg-2.jar:] at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121) [jsf-impl-2.1.7-jbossorg-2.jar:] at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.1.7-jbossorg-2.jar:] at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) [jsf-impl-2.1.7-jbossorg-2.jar:] at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:489) [jbossweb-7.0.13.Final.jar:] at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:] at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:] at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:] at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:] at java.lang.Thread.run(Unknown Source) [rt.jar:1.7.0_25] Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "org.jboss.resteasy.client.core.executors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, at/fhj/ase/ssl/SSLClientHelper, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for resolved class, org/jboss/resteasy/client/core/executors/ApacheHttpClient4Executor, have different Class objects for the type xecutors.ApacheHttpClient4Executor.<init>(Lorg/apache/http/client/HttpClient;Lorg/apache/http/protocol/HttpContext;)V used in the signature at at.fhj.ase.ssl.SSLClientHelper.getSSLClientRequest(SSLClientHelper.java:71) [classes:] at at.fhj.ase.beans.Categories.getCats(Categories.java:39) [classes:] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_25] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.7.0_25] at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.7.0_25] at javax.el.BeanELResolver.getValue(BeanELResolver.java:302) [jboss-el-api_2.2_spec-1.0.0.Final.jar:1.0.0.Final] at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) [jsf-impl-2.1.7-jbossorg-2.jar:] at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) [jsf-impl-2.1.7-jbossorg-2.jar:] at org.apache.el.parser.AstValue.getValue(AstValue.java:169) [jbossweb-7.0.13.Final.jar:] at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189) [jbossweb-7.0.13.Final.jar:] at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109) [jsf-impl-2.1.7-jbossorg-2.jar:] ... 36 more 

I am sure the HttpClient source is great, as it is the same as used on the web service for JUnit tests.

ProjectSetup: The web service is deployed on JBoss AS7.1 (so far everything is working fine) The JSF web client is deployed on a single JBoss instance. Both run through Eclipse. The deployment component for the JSF web client looks like this:

I assume that the communication error was caused by the external (BuildPath and DeploymentAssembly) added by the apache http client library. But how to resolve this?

Please tell me if you need more information. I am very grateful for any help!

Answer 1

The reason you see the error is because RestEasy has a dependency on jQoss modules that are provided as a jboss module. The version you provided contradicts the one provided by JBoss.

Why do you need to pack HTTPClient jars with your web application? Is this for any customer client? In this case, you should use RestEasy, which is the default implementation of JAX-RS on J8SS AS7. This will be the best structure to use for this purpose.

Another option is to add a dependency on the org.apache.httpcomponents module in WEB-INF\jboss-deployment-structure.xml and remove the http-client banks from WEB-INF\lib .