diff --git a/pulsar-functions/runtime/src/main/java/org/apache/pulsar/functions/runtime/instance/JavaInstanceMain.java b/pulsar-functions/runtime/src/main/java/org/apache/pulsar/functions/runtime/instance/JavaInstanceMain.java
index 02029148e911b..fc127cf2d5ee4 100644
--- a/pulsar-functions/runtime/src/main/java/org/apache/pulsar/functions/runtime/instance/JavaInstanceMain.java
+++ b/pulsar-functions/runtime/src/main/java/org/apache/pulsar/functions/runtime/instance/JavaInstanceMain.java
@@ -29,16 +29,15 @@
 import io.grpc.ServerBuilder;
 import io.grpc.stub.StreamObserver;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.pulsar.client.api.*;
+import org.apache.pulsar.functions.fs.LimitsConfig;
 import org.apache.pulsar.functions.proto.Function.FunctionConfig;
 import org.apache.pulsar.functions.proto.InstanceCommunication;
 import org.apache.pulsar.functions.runtime.container.InstanceConfig;
-import org.apache.pulsar.functions.runtime.functioncache.FunctionCacheManagerImpl;
+import org.apache.pulsar.functions.runtime.container.ThreadFunctionContainerFactory;
 import org.apache.pulsar.functions.proto.InstanceControlGrpc;
-import org.apache.pulsar.functions.utils.FunctionConfigUtils;
+import org.apache.pulsar.functions.runtime.spawner.Spawner;
 
 import java.lang.reflect.Type;
-import java.util.HashMap;
 import java.util.Map;
 
 /**
@@ -100,9 +99,6 @@ public class JavaInstanceMain {
     @Parameter(names = "--auto_ack", description = "Enable Auto Acking?\n")
     protected String autoAck = "true";
 
-    private Thread fnThread;
-    private JavaInstanceRunnable javaInstanceRunnable;
-
     private Server server;
 
     public JavaInstanceMain() { }
@@ -143,20 +139,28 @@ public void start() throws Exception {
             Map<String, String> userConfigMap = new Gson().fromJson(userConfig, type);
             functionConfigBuilder.putAllUserConfig(userConfigMap);
         }
-        instanceConfig.setFunctionConfig(functionConfigBuilder.build());
+        FunctionConfig functionConfig = functionConfigBuilder.build();
+        instanceConfig.setFunctionConfig(functionConfig);
+
+        LimitsConfig limitsConfig = new LimitsConfig();
+        limitsConfig.setMaxBufferedTuples(maxBufferedTuples);
 
-        log.info("Starting JavaInstanceMain with {}", instanceConfig);
-        this.javaInstanceRunnable = new JavaInstanceRunnable(
-                instanceConfig,
+        ThreadFunctionContainerFactory containerFactory = new ThreadFunctionContainerFactory(
+                "LocalRunnerThreadGroup",
                 maxBufferedTuples,
-                new FunctionCacheManagerImpl(),
-                jarFile,
-                PulsarClient.create(pulsarServiceUrl, new ClientConfiguration()),
+                pulsarServiceUrl,
                 stateStorageServiceUrl);
-        this.fnThread = new Thread(javaInstanceRunnable, FunctionConfigUtils.getFullyQualifiedName(instanceConfig.getFunctionConfig()));
+
+        Spawner spawner = Spawner.createSpawner(
+                functionConfig,
+                limitsConfig,
+                jarFile,
+                containerFactory,
+                null,
+                0);
 
         server = ServerBuilder.forPort(port)
-                .addService(new InstanceControlImpl(javaInstanceRunnable))
+                .addService(new InstanceControlImpl(spawner))
                 .build()
                 .start();
         log.info("JaveInstance Server started, listening on " + port);
@@ -164,25 +168,19 @@ public void start() throws Exception {
             @Override
             public void run() {
                 // Use stderr here since the logger may have been reset by its JVM shutdown hook.
-                System.err.println("*** shutting down gRPC server since JVM is shutting down");
                 try {
-                    JavaInstanceMain.this.stop();
+                    server.shutdown();
+                    spawner.close();
                 } catch (Exception ex) {
                     System.err.println(ex);
                 }
-                System.err.println("*** server shut down");
             }
         });
-        fnThread.start();
-        server.awaitTermination();
-    }
-
-    private void stop() throws Exception {
-        if (server != null) {
-            server.shutdown();
-        }
-        fnThread.interrupt();
-        fnThread.join();
+        log.info("Starting spawner");
+        spawner.start();
+        spawner.join();
+        log.info("Spawner quit, shutting down JavaInstance");
+        server.shutdown();
     }
 
     public static void main(String[] args) throws Exception {
@@ -196,23 +194,21 @@ public static void main(String[] args) throws Exception {
     }
 
     static class InstanceControlImpl extends InstanceControlGrpc.InstanceControlImplBase {
-        private JavaInstanceRunnable javaInstanceRunnable;
+        private Spawner spawner;
 
-        public InstanceControlImpl(JavaInstanceRunnable javaInstanceRunnable) {
-            this.javaInstanceRunnable = javaInstanceRunnable;
+        public InstanceControlImpl(Spawner spawner) {
+            this.spawner = spawner;
         }
 
         @Override
         public void getFunctionStatus(Empty request, StreamObserver<InstanceCommunication.FunctionStatus> responseObserver) {
-            InstanceCommunication.FunctionStatus.Builder builder = javaInstanceRunnable.getFunctionStatus();
-            String failureException = javaInstanceRunnable.getFailureException() != null
-                    ? javaInstanceRunnable.getFailureException().getMessage() : "";
-            InstanceCommunication.FunctionStatus response = builder
-                    .setRunning(true)
-                    .setFailureException(failureException)
-                    .build();
-            responseObserver.onNext(response);
-            responseObserver.onCompleted();
+            try {
+                InstanceCommunication.FunctionStatus response = spawner.getFunctionStatus().get();
+                responseObserver.onNext(response);
+                responseObserver.onCompleted();
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
         }
     }
 }