diff --git a/shell.tui/src/main/java/org/apache/felix/shell/tui/Activator.java b/shell.tui/src/main/java/org/apache/felix/shell/tui/Activator.java
index b8d025b..1b94a62 100644
--- a/shell.tui/src/main/java/org/apache/felix/shell/tui/Activator.java
+++ b/shell.tui/src/main/java/org/apache/felix/shell/tui/Activator.java
@@ -83,10 +83,13 @@
         // since one might already be available.
         initializeService();
 
-        // Start impl thread.
-        m_thread = new Thread(
-            m_runnable = new ShellTuiRunnable(),
-            "Felix Shell TUI");
+        synchronized (this)
+        {
+            // Start impl thread.
+            m_thread = new Thread(
+                m_runnable = new ShellTuiRunnable(),
+                "Felix Shell TUI");
+        }
         m_thread.start();
     }
 
@@ -107,16 +110,19 @@
 
     public void stop(BundleContext context)
     {
-        if (m_runnable != null)
+        synchronized (this)
         {
-            m_runnable.stop();
-            m_thread.interrupt();
+            if (m_runnable != null)
+            {
+                m_runnable.stop();
+                m_thread.interrupt();
+            }
         }
     }
 
     private class ShellTuiRunnable implements Runnable
     {
-        private boolean stop = false;
+        private volatile boolean stop = false;
 
         public void stop()
         {
@@ -127,15 +133,22 @@
         {
             String line = null;
             BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
-
             while (!stop)
             {
                 System.out.print("-> ");
 
                 try
                 {
+                    while (!in.ready())
+                    {
+                        Thread.sleep(20);
+                    }
                     line = in.readLine();
                 }
+                catch (InterruptedException ex)
+                {
+                    continue;
+                }
                 catch (IOException ex)
                 {
                     System.err.println("Could not read input, please try again.");
@@ -175,4 +188,4 @@
             }
         }
     }
-}
\ No newline at end of file
+}