* Fixed the FIXME in createInstance where the method failed to ensures that...

* Fixed the FIXME in createInstance where the method failed to ensures that there will be only one naming service instance.

core/java/src/net/i2p/client/naming/NamingService.java

@@ -31,6 +31,8 @@ public abstract class NamingService {
     protected final Set<NamingServiceListener> _listeners;
     protected final Set<NamingServiceUpdater> _updaters;
 
+    private static NamingService instance;
+
     /** what classname should be used as the naming service impl? */
     public static final String PROP_IMPL = "i2p.naming.impl";
     private static final String DEFAULT_IMPL = "net.i2p.client.naming.BlockfileNamingService";
@@ -451,26 +453,27 @@ public abstract class NamingService {
      * choose the implementation from the "i2p.naming.impl" system
      * property.
      *
-     * FIXME Actually, it doesn't ensure that. Only call this once!!!
      */
     public static final synchronized NamingService createInstance(I2PAppContext context) {
-        NamingService instance = null;
-        String impl = context.getProperty(PROP_IMPL, DEFAULT_IMPL);
+        if (instance instanceof NamingService) {
+            return instance;
+        }
+        String impl = context.getProperty(PROP_IMPL, DEFAULT_IMPL); 
         try {
             Class cls = Class.forName(impl);
             Constructor con = cls.getConstructor(new Class[] { I2PAppContext.class });
             instance = (NamingService)con.newInstance(new Object[] { context });
-        } catch (Exception ex) {
-            Log log = context.logManager().getLog(NamingService.class);
-            // Blockfile may throw RuntimeException but HostsTxt won't
-            if (!impl.equals(BACKUP_IMPL)) {
-                log.error("Cannot load naming service " + impl + ", using HostsTxtNamingService", ex);
-                instance = new HostsTxtNamingService(context);
-            } else {
-                log.error("Cannot load naming service " + impl + ", only .b32.i2p lookups will succeed", ex);
-                instance = new DummyNamingService(context);
-            }
-        }
+        } catch (Exception ex) { 
+            Log log = context.logManager().getLog(NamingService.class); 
+            // Blockfile may throw RuntimeException but HostsTxt won't 
+            if (!impl.equals(BACKUP_IMPL)) { 
+                log.error("Cannot load naming service " + impl + ", using HostsTxtNamingService", ex); 
+                instance = new HostsTxtNamingService(context); 
+            } else { 
+                log.error("Cannot load naming service " + impl + ", only .b32.i2p lookups will succeed", ex); 
+                instance = new DummyNamingService(context); 
+            } 
+        } 
         return instance;
     }