3252821 - AS Java upgrade fails - com.sap.engine.services.rmi_p4.P4ConnectionException: The stub cannot establish connection

Software upgrade fails by "Deploying Software Components" phase. SUM logs show:

DEPLOY-COMPONENTS_<x>.LOG:

[...]
Deployment error. Cannot send items to AS Java for deployment. See log /usr/sap/<SID>/SUM/sdt/log/SUM/deploy_api.<x>.log for details.
com.sap.engine.services.dc.api.deploy.TransportException: [ERROR CODE DPL.DCAPI.1028] EOFException.
Reason: End of stream is reached unexpectedly during input from Socket[addr=<IP_adress>,port=<port>,localport=<localport>]
[...]

deploy_api.<x>.trc:

[...]
Caused by: com.sap.engine.services.rmi_p4.P4ConnectionException: The stub cannot establish connection
 at com.sap.engine.services.rmi_p4.P4ObjectBrokerClientImpl.getException(P4ObjectBrokerClientImpl.java:831)
 at com.sap.engine.services.rmi_p4.P4ObjectBrokerClientImpl.getException(P4ObjectBrokerClientImpl.java:813)
 at com.sap.engine.services.rmi_p4.StubImpl.p4_invoke(StubImpl.java:193)
 ... 30 more
[...]

• SAP NetWeaver Application Server Java all versions
• Software Update Manager

Software update manager, SUM upgrade, AS Java upgrade, Java upgrade, The stub cannot establish connection, End of stream is reached unexpectedly during input from Socket, com.sap.engine.services.rmi_p4.P4ConnectionException, java.io.EOFException , KBA , BC-UPG-TLS-TLJ , Upgrade tools for Java , BC-JAS-SEC , Security, User Management , BC-JAS-DPL , Deployment , BC-JAS-COR-RMT , RMI, P4, CORBA, IIOP , Problem