In the Prosys OPC UA Java SDK – Server Tutorial is written:

If your application does not use security, you may also create the identity without
any certificate by using the default constructor. However, you should always set
the ApplicationDescription to the identity.

But if I try doing this:

….
ApplicationIdentity newIdentity = new ApplicationIdentity();
newIdentity.setApplicationDescription(appDescription);
server.setApplicationIdentity(newIdentity);
server.setSecurityModes(SecurityMode.NON_SECURE);
server.addUserTokenPolicy(UserTokenPolicy.ANONYMOUS);
server.init();

I got following Exception:

Exception in thread “main” java.lang.IllegalArgumentException: null arg
at org.opcfoundation.ua.transport.security.KeyPair.(KeyPair.java:117)
Disconnected from the target VM, address: ‘127.0.0.1:56922’, transport: ‘socket’
at com.prosysopc.ua.ApplicationIdentity.getCertificates(SourceFile:960)
at com.prosysopc.ua.server.UaServer.bj(SourceFile:2116)
at com.prosysopc.ua.server.UaServer.init(SourceFile:1125)
at de.siemens.mcRail.IntermediateServer.IntermediateServer.initialize(IntermediateServer.java:204)
at de.siemens.mcRail.IntermediateServer.IntermediateServer.main(IntermediateServer.java:57)

Whats going wrong?