I am currently facing an issue with the Websphere Deployer Plugin, Jenkins is running on a Websphere 8.5.5.9 server with the 1.8_64 JDK.

[3/1/17 18:23:23:870 EST] 000000c4 SystemErr R com.ibm.websphere.management.exception.AdminException:
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at com.ibm.websphere.management.application.AppManagementProxy.proxyInvokeNoRet(AppManagementProxy.java:173)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at com.ibm.websphere.management.application.AppManagementProxy.installApplication(AppManagementProxy.java:510)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at org.jenkinsci.plugins.websphere.services.deployment.WebSphereDeploymentService.installArtifact(WebSphereDeploymentService.java:237)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at org.jenkinsci.plugins.websphere_deployer.WebSphereDeployerPlugin.deployArtifact(WebSphereDeployerPlugin.java:227)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at org.jenkinsci.plugins.websphere_deployer.WebSphereDeployerPlugin.perform(WebSphereDeployerPlugin.java:201)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.tasks.BuildStepMonitor$3.perform(BuildStepMonitor.java:45)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:779)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:720)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.Build$BuildExecution.post2(Build.java:185)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:665)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.Run.execute(Run.java:1753)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.ResourceController.execute(ResourceController.java:98)
[3/1/17 18:23:23:871 EST] 000000c4 SystemErr R at hudson.model.Executor.run(Executor.java:404)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R Caused by: com.ibm.websphere.management.exception.ConnectorException: ADMC0009E: The system failed to make the SOAP RPC call: invoke
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient.invokeTemplateOnce(SOAPConnectorClient.java:894)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient.invokeTemplate(SOAPConnectorClient.java:689)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient.invokeTemplate(SOAPConnectorClient.java:679)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient.invoke(SOAPConnectorClient.java:665)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient.invoke(SOAPConnectorClient.java:487)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.sun.proxy.$Proxy76.invoke(Unknown Source)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.ws.management.AdminClientImpl.invoke(AdminClientImpl.java:224)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at com.ibm.websphere.management.application.AppManagementProxy.proxyInvokeNoRet(AppManagementProxy.java:167)
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R ... 13 more
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R Caused by: [SOAPException: faultCode=SOAP-ENV:Client; msg=com.ibm.ws.management.configservice.ConfigServiceServerProxy; targetException=java.io.NotSerializableException: com.ibm.ws.management.configservice.ConfigServiceServerProxy]
[3/1/17 18:23:23:872 EST] 000000c4 SystemErr R at org.apache.soap.transport.http.SOAPHTTPConnection.send(SOAPHTTPConnection.java:479)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at org.apache.soap.rpc.Call.WASinvoke(Call.java:510)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient$8.run(SOAPConnectorClient.java:852)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at com.ibm.ws.security.util.AccessController.doPrivileged(AccessController.java:118)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at com.ibm.ws.management.connector.soap.SOAPConnectorClient.invokeTemplateOnce(SOAPConnectorClient.java:845)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R ... 20 more
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R org.jenkinsci.plugins.websphere.services.deployment.DeploymentServiceException: Failed to install artifact:
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at org.jenkinsci.plugins.websphere.services.deployment.WebSphereDeploymentService.installArtifact(WebSphereDeploymentService.java:251)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at org.jenkinsci.plugins.websphere_deployer.WebSphereDeployerPlugin.deployArtifact(WebSphereDeployerPlugin.java:227)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at org.jenkinsci.plugins.websphere_deployer.WebSphereDeployerPlugin.perform(WebSphereDeployerPlugin.java:201)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at hudson.tasks.BuildStepMonitor$3.perform(BuildStepMonitor.java:45)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:779)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:720)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at hudson.model.Build$BuildExecution.post2(Build.java:185)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:665)
[3/1/17 18:23:23:873 EST] 000000c4 SystemErr R at hudson.model.Run.execute(Run.java:1753)
[3/1/17 18:23:23:874 EST] 000000c4 SystemErr R at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
[3/1/17 18:23:23:874 EST] 000000c4 SystemErr R at hudson.model.ResourceController.execute(ResourceController.java:98)
[3/1/17 18:23:23:874 EST] 000000c4 SystemErr R at hudson.model.Executor.run(Executor.java:404)

I have the Jenkins class loader set to Parent_Last.

The issue seems to be a class not implementing the Serializable interface, but I am unsure how to overcome this.
Caused by: [SOAPException: faultCode=SOAP-ENV:Client; msg=com.ibm.ws.management.configservice.ConfigServiceServerProxy; targetException=java.io.NotSerializableException: com.ibm.ws.management.configservice.ConfigServiceServerProxy]