Avoid doing interrupt on main thread when termination is requested

This had some nasty side effects where ClosedByInterruptExceptions
prevented the system from shutdown properly.

community/server/src/main/java/org/neo4j/server/ServerBootstrapper.java

@@ -49,8 +49,8 @@
 public abstract class ServerBootstrapper implements Bootstrapper
 {
     public static final int OK = 0;
-    public static final int WEB_SERVER_STARTUP_ERROR_CODE = 1;
-    public static final int GRAPH_DATABASE_STARTUP_ERROR_CODE = 2;
+    private static final int WEB_SERVER_STARTUP_ERROR_CODE = 1;
+    private static final int GRAPH_DATABASE_STARTUP_ERROR_CODE = 2;
     private static final String SIGTERM = "TERM";
     private static final String SIGINT = "INT";
 
@@ -83,7 +83,7 @@ public static int start( Bootstrapper boot, String... argv )
     public final int start( File homeDir, Optional<File> configFile, Map<String, String> configOverrides )
     {
         addShutdownHook();
-        installSignalHandler();
+        installSignalHandlers();
         try
         {
             // Create config file from arguments
@@ -184,31 +184,18 @@ private static LogProvider setupLogging( Config config )
     }
 
     // Exit gracefully if possible
-    private void installSignalHandler()
+    private void installSignalHandlers()
+    {
+        installSignalHandler( SIGTERM ); // SIGTERM is invoked when system service is stopped
+        installSignalHandler( SIGINT ); // SIGINT is invoked when user hits ctrl-c  when running `neo4j console`
+    }
+
+    private void installSignalHandler( String sig )
     {
         try
         {
-            /*
-             * We want to interrupt the main thread which has start()ed lifecycle instances that may be blocked
-             * somewhere. If we don't do that, then the JVM will hang on the final join() for non daemon threads.
-             */
-            Thread t = Thread.currentThread();
-            log.debug( "Installing signal handler to interrupt thread named " + t.getName() );
-            // SIGTERM is invoked when system service is stopped
-            Signal.handle( new Signal( SIGTERM ), signal ->
-            {
-                t.interrupt();
-                System.exit( 0 );
-            } );
-        }
-        catch ( Throwable e )
-        {
-            log.warn( "Unable to install signal handler. Exit code may not be 0 on graceful shutdown.", e );
-        }
-        try
-        {
-            // SIGINT is invoked when user hits ctrl-c  when running `neo4j console`
-            Signal.handle( new Signal( SIGINT ), signal -> System.exit( 0 ) );
+            // System.exit() will trigger the shutdown hook
+            Signal.handle( new Signal( sig ), signal -> System.exit( 0 ) );
         }
         catch ( Throwable e )
         {

enterprise/causal-clustering/src/test/java/org/neo4j/causalclustering/discovery/HazelcastCoreTopologyServiceTest.java

@@ -0,0 +1,51 @@
+package org.neo4j.causalclustering.discovery;
+
+import org.junit.Test;
+
+import java.util.UUID;
+
+import org.neo4j.causalclustering.core.CausalClusteringSettings;
+import org.neo4j.causalclustering.identity.MemberId;
+import org.neo4j.kernel.configuration.BoltConnector;
+import org.neo4j.kernel.configuration.Config;
+import org.neo4j.kernel.impl.scheduler.CentralJobScheduler;
+import org.neo4j.logging.NullLogProvider;
+import org.neo4j.ports.allocation.PortAuthority;
+
+import static org.neo4j.causalclustering.core.CausalClusteringSettings.initial_discovery_members;
+import static org.neo4j.helpers.collection.MapUtil.stringMap;
+
+public class HazelcastCoreTopologyServiceTest
+{
+    @Test( timeout = 120_000)
+    public void shouldBeAbleToStartAndStoreWithoutSuccessfulJoin()
+    {
+        CentralJobScheduler jobScheduler = new CentralJobScheduler();
+        jobScheduler.init();
+        HostnameResolver hostnameResolver = new NoOpHostnameResolver();
+
+        // Random members that does not exists, discovery will never succeed
+        String initialHosts = "localhost:" + PortAuthority.allocatePort() + ",localhost:" + PortAuthority.allocatePort();
+        Config config = config();
+        config.augment( initial_discovery_members, initialHosts );
+        HazelcastCoreTopologyService service = new HazelcastCoreTopologyService( config,
+                new MemberId( UUID.randomUUID() ),
+                jobScheduler,
+                NullLogProvider.getInstance(),
+                NullLogProvider.getInstance(),
+                hostnameResolver,
+                new TopologyServiceNoRetriesStrategy() );
+        service.start();
+        Thread.yield();
+        service.stop();
+    }
+
+    private static Config config()
+    {
+        return Config.defaults( stringMap(
+                CausalClusteringSettings.raft_advertised_address.name(), "127.0.0.1:7000",
+                CausalClusteringSettings.transaction_advertised_address.name(), "127.0.0.1:7001",
+                new BoltConnector( "bolt" ).enabled.name(), "true",
+                new BoltConnector( "bolt" ).advertised_address.name(), "127.0.0.1:7002" ) );
+    }
+}