nd4j-parameter-server-parent/nd4j-parameter-server-node/src/main/java/org/nd4j/parameterserver/distributed/VoidParameterServer.java
public void shutdown() {
        /**
         * Probably we don't need this method in practice
         */
        if (initLocker.get() && shutdownLocker.compareAndSet(false, true)) {
            // do shutdown
            log.info("Shutting down transport...");

            // we just sending out ShutdownRequestMessage
            //transport.sendMessage(new ShutdownRequestMessage());
            transport.shutdown();

            executor.shutdown();

        }
    }
public void shutdown() {
        /**
         * Probably we don't need this method in practice
         */
        if (initLocker.get() && shutdownLocker.compareAndSet(false, true)) {
            // do shutdown
            log.info("Shutting down transport...");

            // we just sending out ShutdownRequestMessage
            //transport.sendMessage(new ShutdownRequestMessage());
            transport.shutdown();

            executor.shutdown();

        }
    }
This method initiates shutdown sequence for this instance.

PLEASE NOTE: This method is blocking for first caller only