Hello, we have developed an OPC server using the 2.2.2-638 version.
Everything seems to work fine, if we’re using java 8. I couldn’t find documentation saying the SDK was java 8 only compatible.
When we use java 7, we get java.lang.VerifyError: Cannot inherit from final class.

Has anyone seen this type of error before. It looks like an apache library version mismatch, but if that’s the case, it’s strange that going to java 8 fixes the issue.

Here is the error in the startup of our Wildfly application server, which we’ve built the OPC server into.

2016-05-25 10:12:35,876 WARN [org.jboss.modules] (MSC service thread 1-2) Failed to define class org.apache.http.params.SyncBasicHttpParams in Module “deployment.ProductAdmin.ear:main” from Service Module Loader: java.lang.VerifyError: Cannot inherit from final class
at java.lang.ClassLoader.defineClass1(Native Method) [rt.jar:1.7.0_95]
at java.lang.ClassLoader.defineClass(ClassLoader.java:800) [rt.jar:1.7.0_95]
at org.jboss.modules.ModuleClassLoader.doDefineOrLoadClass(ModuleClassLoader.java:361) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:482) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:277) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader$1.loadClassLocal(ModuleClassLoader.java:92) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.Module.loadModuleClass(Module.java:568) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:205) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:459) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:408) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:389) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:134) [jboss-modules.jar:1.3.3.Final]
at org.opcfoundation.ua.transport.https.HttpsServer.(Unknown Source) [Opc.Ua.Stack-1.02.337.8.jar:1.02.337.8]
at org.opcfoundation.ua.application.Application.getOrCreateHttpsServer(Unknown Source) [Opc.Ua.Stack-1.02.337.8.jar:1.02.337.8]
at com.prosysopc.ua.server.UaServer.b(Unknown Source) [Prosys-OPC-UA-Java-SDK-Client-Server-Evaluation-2.2.2-638.jar:2.2.2.638]
at com.prosysopc.ua.server.UaServer.start(Unknown Source) [Prosys-OPC-UA-Java-SDK-Client-Server-Evaluation-2.2.2-638.jar:2.2.2.638]
at com.Mycompany.product.opc.server.OPCServer.startOPCServer(OPCServer.java:59) [edmbusiness.jar:4.7.0 (build: SVNTag=18078)]
at com.Mycompany.product.webapp.servlets.InitServlet.init(InitServlet.java:479) [classes:4.7.0 (build: SVNTag=18078)]
at javax.servlet.GenericServlet.init(GenericServlet.java:244) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:117) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at org.wildfly.extension.undertow.security.RunAsLifecycleInterceptor.init(RunAsLifecycleInterceptor.java:79)
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:103) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at io.undertow.servlet.core.ManagedServlet$DefaultInstanceStrategy.start(ManagedServlet.java:220) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at io.undertow.servlet.core.ManagedServlet.createServlet(ManagedServlet.java:125) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at io.undertow.servlet.core.DeploymentManagerImpl.start(DeploymentManagerImpl.java:508) [undertow-servlet-1.1.0.Final.jar:1.1.0.Final]
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:88)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.start(UndertowDeploymentService.java:72)
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1948)
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1881)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_95]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_95]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_95]

2016-05-25 10:12:35,878 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-2) MSC000001: Failed to start service jboss.undertow.deployment.default-server.default-host./edm: org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./edm: Failed to start service
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1904) [jboss-msc-1.2.2.Final.jar:1.2.2.Final]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_95]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_95]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_95]
Caused by: java.lang.VerifyError: Cannot inherit from final class
at java.lang.ClassLoader.defineClass1(Native Method) [rt.jar:1.7.0_95]
at java.lang.ClassLoader.defineClass(ClassLoader.java:800) [rt.jar:1.7.0_95]
at org.jboss.modules.ModuleClassLoader.doDefineOrLoadClass(ModuleClassLoader.java:361) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:482) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:277) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader$1.loadClassLocal(ModuleClassLoader.java:92) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.Module.loadModuleClass(Module.java:568) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:205) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:459) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:408) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:389) [jboss-modules.jar:1.3.3.Final]
at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:134) [jboss-modules.jar:1.3.3.Final]
at org.opcfoundation.ua.transport.https.HttpsServer.(Unknown Source)
at org.opcfoundation.ua.application.Application.getOrCreateHttpsServer(Unknown Source)
at com.prosysopc.ua.server.UaServer.b(Unknown Source)
at com.prosysopc.ua.server.UaServer.start(Unknown Source)
at com.Mycompany.product.opc.server.MyOPCServer.startOPCServer(OPCServer.java:59)
at com.Mycompany.product.webapp.servlets.InitServlet.init(InitServlet.java:479)
at javax.servlet.GenericServlet.init(GenericServlet.java:244)
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:117)
at org.wildfly.extension.undertow.security.RunAsLifecycleInterceptor.init(RunAsLifecycleInterceptor.java:79)
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:103)
at io.undertow.servlet.core.ManagedServlet$DefaultInstanceStrategy.start(ManagedServlet.java:220)
at io.undertow.servlet.core.ManagedServlet.createServlet(ManagedServlet.java:125)
at io.undertow.servlet.core.DeploymentManagerImpl.start(DeploymentManagerImpl.java:508)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:88)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.start(UndertowDeploymentService.java:72)
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1948) [jboss-msc-1.2.2.Final.jar:1.2.2.Final]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1881) [jboss-msc-1.2.2.Final.jar:1.2.2.Final]
… 3 more