Fixes btraceio#136 and a introduced Bug of btraceio#93 - make sure th…

…e BTrace Runtime is stopped before exitting the jvm

- no client is connected, only the agent with a script
- make sure the PrintWriter is always flushed after printing with GridDataCommand

src/share/classes/com/sun/btrace/agent/Client.java

@@ -269,6 +269,12 @@ protected Class loadClass(InstrumentCommand instr) throws IOException {
         Main.dumpClass(className, className, btraceCode);
         if (debug) Main.debugPrint("creating BTraceRuntime instance for " + className);
         this.runtime = new BTraceRuntime(className, args, this, inst);
+        Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
+            @Override
+            public void run() {
+                runtime.handleExit(0);
+            }
+        }));
         if (debug) Main.debugPrint("created BTraceRuntime instance for " + className);
         if (debug) Main.debugPrint("removing @OnMethod, @OnProbe methods");
         byte[] codeBuf = removeMethods(btraceCode);

src/share/classes/com/sun/btrace/agent/Main.java

@@ -88,17 +88,6 @@ public Thread newThread(Runnable r) {
 
     private static final ExecutorService serializedExecutor = Executors.newSingleThreadExecutor(daemonizedThreadFactory);
 
-    private static void registerExitHook(final Client c) {
-        Runtime.getRuntime().addShutdownHook(new Thread(
-            new Runnable() {
-                @Override
-                public void run() {
-                    BTraceRuntime rt = c.getRuntime();
-                    if (rt != null) rt.handleExit(0);
-                }
-            }));
-    }
-
     public static void premain(String args, Instrumentation inst) {
         main(args, inst);
     }
@@ -413,7 +402,6 @@ private static void startServer() {
                 Socket sock = ss.accept();
                 if (isDebug()) debugPrint("client accepted " + sock);
                 Client client = new RemoteClient(inst, sock);
-                registerExitHook(client);
                 handleNewClient(client).get();
             } catch (RuntimeException | IOException | ExecutionException re) {
                 if (isDebug()) debugPrint(re);

src/share/classes/com/sun/btrace/comm/GridDataCommand.java

@@ -131,6 +131,7 @@ public void print(PrintWriter out) {
                 out.println(line);
             }
         }
+        out.flush();
     }
 
     private static final HashMap<Class< ? >, String> typeFormats = new HashMap<Class< ? >, String>();