NetWorker REST API fails to load with "librestapi64.so already loaded in another classloader"

• NetWorker RESTAPI fails to load throwing: "java.lang.UnsatisfiedLinkError: Native Library /nsr/authc/webapps/nwrestapi/WEB-INF/lib/librestapi64.so already loaded in another classloader"

HTTP Status 500 - Servlet.init() for servlet nwrestapi threw exception

type Exception report

message Servlet.init() for servlet nwrestapi threw exception

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Servlet.init() for servlet nwrestapi threw exception
	org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
	org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
	org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
	org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1775)
	org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1734)
	java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	java.lang.Thread.run(Unknown Source)

root cause

java.lang.UnsatisfiedLinkError: Native Library /nsr/authc/webapps/nwrestapi/WEB-INF/lib/librestapi64.so already loaded in another classloader
	java.lang.ClassLoader.loadLibrary0(Unknown Source)
	java.lang.ClassLoader.loadLibrary(Unknown Source)
	java.lang.Runtime.load0(Unknown Source)
	java.lang.System.load(Unknown Source)
	com.emc.nw.webapi.WebApiServlet.loadDbSessionModules(WebApiServlet.java:75)
	com.emc.nw.webapi.WebApiServlet.init(WebApiServlet.java:55)
	org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
	org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
	org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
	org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1775)
	org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1734)
	java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	java.lang.Thread.run(Unknown Source)

• The NetWorker server version and Operating System meet compatibility requirements.
• The lsof command shows the library in a DEL state:

[root@nw_server ~]#  lsof | grep librestapi64
jsvc       4543 nsrtomcat  DEL       REG              253,2   14881546   67764661 /nsr/authc/webapps/nwrestapi/WEB-INF/lib/librestapi64.so

1. Reboot the server to flush and reload memory: NetWorker RESTAPI fails to load with "Native Library /nsr/authc/webapps/nwrestapi/WEB-INF/lib/librestapi64.so already loaded in another classloader"
2. Import emcauthctomcat.cer (if missing) to the Java cacerts keystore: NetWorker: NetWorker REST API emcauthctomcat certificate removed from cacerts keystore

The java.lang.UnsatisfiedLinkError can also appear if the NetWorker version does not support the operating system of the NetWorker server: NetWorker: REST API requests fail with HTTP 500 java.lang.UnsatisfiedLinkError