Fixed IceLocatorDiscovery race condition, fixes #555

8 files changed, 224 insertions, 35 deletions

diff --git a/cpp/src/IceLocatorDiscovery/PluginI.cpp b/cpp/src/IceLocatorDiscovery/PluginI.cpp
index fde4c106e97..92295c261c0 100644
--- a/cpp/src/IceLocatorDiscovery/PluginI.cpp
+++ b/cpp/src/IceLocatorDiscovery/PluginI.cpp
@@ -106,9 +106,9 @@ private:
 
     LookupPrxPtr _lookup;
     vector<pair<LookupPrxPtr, LookupReplyPrxPtr> > _lookups;
-    const IceUtil::Time _timeout;
-    const int _retryCount;
-    const IceUtil::Time _retryDelay;
+    IceUtil::Time _timeout;
+    int _retryCount;
+    IceUtil::Time _retryDelay;
     const IceUtil::TimerPtr _timer;
     const int _traceLevel;
 
@@ -119,6 +119,7 @@ private:
     Ice::LocatorPrxPtr _voidLocator;
 
     IceUtil::Time _nextRetry;
+    bool _pending;
     int _pendingRetryCount;
     size_t _failureCount;
     bool _warnOnce;
@@ -574,10 +575,24 @@ LocatorI::LocatorI(const string& name,
     _warned(false),
     _locator(lookup->ice_getCommunicator()->getDefaultLocator()),
     _voidLocator(voidLocator),
+    _pending(false),
     _pendingRetryCount(0),
     _failureCount(0),
     _warnOnce(true)
 {
+    if(_timeout < IceUtil::Time::milliSeconds(0))
+    {
+        _timeout = IceUtil::Time::milliSeconds(300);
+    }
+    if(_retryCount < 0)
+    {
+        _retryCount = 0;
+    }
+    if(_retryDelay < IceUtil::Time::milliSeconds(0))
+    {
+        _retryDelay = IceUtil::Time::milliSeconds(0);
+    }
+
     //
     // Create one lookup proxy per endpoint from the given proxy. We want to send a multicast
     // datagram on each endpoint.
@@ -669,7 +684,7 @@ LocatorI::getLocators(const string& instanceName, const IceUtil::Time& waitTime)
     else
     {
         Lock sync(*this);
-        while(_locators.find(instanceName) == _locators.end() && _pendingRetryCount > 0)
+        while(_locators.find(instanceName) == _locators.end() && _pending)
         {
             timedWait(waitTime);
         }
@@ -725,10 +740,11 @@ LocatorI::foundLocator(const Ice::LocatorPrxPtr& locator)
         return;
     }
 
-    if(_pendingRetryCount > 0) // No need to retry, we found a locator.
+    if(_pending) // No need to continue, we found a locator.
     {
         _timer->cancel(ICE_SHARED_FROM_THIS);
         _pendingRetryCount = 0;
+        _pending = false;
     }
 
     if(_traceLevel > 0)
@@ -821,8 +837,9 @@ LocatorI::invoke(const Ice::LocatorPrxPtr& locator, const RequestPtr& request)
             _pendingRequests.push_back(request);
         }
 
-        if(_pendingRetryCount == 0) // No request in progress
+        if(!_pending) // No request in progress
         {
+            _pending = true;
             _failureCount = 0;
             _pendingRetryCount = _retryCount;
             try
@@ -877,6 +894,7 @@ LocatorI::invoke(const Ice::LocatorPrxPtr& locator, const RequestPtr& request)
                     (*p)->invoke(_voidLocator);
                 }
                 _pendingRequests.clear();
+                _pending = false;
                 _pendingRetryCount = 0;
             }
         }
@@ -887,13 +905,14 @@ void
 LocatorI::exception(const Ice::LocalException& ex)
 {
     Lock sync(*this);
-    if(++_failureCount == _lookups.size() && _pendingRetryCount > 0)
+    if(++_failureCount == _lookups.size() && _pending)
     {
         //
         // All the lookup calls failed, cancel the timer and propagate the error to the requests.
         //
         _timer->cancel(ICE_SHARED_FROM_THIS);
         _pendingRetryCount = 0;
+        _pending = false;
 
         if(_warnOnce)
         {
@@ -932,8 +951,15 @@ void
 LocatorI::runTimerTask()
 {
     Lock sync(*this);
-    if(--_pendingRetryCount > 0)
+    if(!_pending)
     {
+        assert(_pendingRequests.empty());
+        return; // The request failed
+    }
+
+    if(_pendingRetryCount > 0)
+    {
+        --_pendingRetryCount;
         try
         {
             if(_traceLevel > 1)
@@ -976,6 +1002,9 @@ LocatorI::runTimerTask()
         _pendingRetryCount = 0;
     }
 
+    assert(_pendingRetryCount == 0);
+    _pending = false;
+
     if(_traceLevel > 0)
     {
         Ice::Trace out(_lookup->ice_getCommunicator()->getLogger(), "Lookup");
diff --git a/cpp/test/IceGrid/simple/AllTests.cpp b/cpp/test/IceGrid/simple/AllTests.cpp
index 037d5627447..8ac52b2b58a 100644
--- a/cpp/test/IceGrid/simple/AllTests.cpp
+++ b/cpp/test/IceGrid/simple/AllTests.cpp
@@ -165,6 +165,26 @@ allTests(Test::TestHelper* helper)
 
             initData.properties = communicator->getProperties()->clone();
             initData.properties->setProperty("Ice.Default.Locator", "");
+            initData.properties->setProperty("IceLocatorDiscovery.RetryCount", "0");
+            initData.properties->setProperty("Ice.Plugin.IceLocatorDiscovery",
+                                             "IceLocatorDiscovery:createIceLocatorDiscovery");
+            initData.properties->setProperty("IceLocatorDiscovery.Lookup",
+                                             "udp -h " + multicast + " --interface unknown");
+            com = Ice::initialize(initData);
+            test(com->getDefaultLocator());
+            try
+            {
+                com->stringToProxy("test @ TestAdapter")->ice_ping();
+                test(false);
+            }
+            catch(const Ice::NoEndpointException&)
+            {
+            }
+            com->destroy();
+
+            initData.properties = communicator->getProperties()->clone();
+            initData.properties->setProperty("Ice.Default.Locator", "");
+            initData.properties->setProperty("IceLocatorDiscovery.RetryCount", "1");
             initData.properties->setProperty("Ice.Plugin.IceLocatorDiscovery",
                                              "IceLocatorDiscovery:createIceLocatorDiscovery");
             {
diff --git a/csharp/src/IceLocatorDiscovery/PluginI.cs b/csharp/src/IceLocatorDiscovery/PluginI.cs
index c0698ed93ff..2bc28527f1b 100644
--- a/csharp/src/IceLocatorDiscovery/PluginI.cs
+++ b/csharp/src/IceLocatorDiscovery/PluginI.cs
@@ -139,14 +139,27 @@ namespace IceLocatorDiscovery
         {
             _lookup = lookup;
             _timeout = properties.getPropertyAsIntWithDefault(name + ".Timeout", 300);
+            if(_timeout < 0)
+            {
+                _timeout = 300;
+            }
             _retryCount = properties.getPropertyAsIntWithDefault(name + ".RetryCount", 3);
+            if(_retryCount < 0)
+            {
+                _retryCount = 0;
+            }
             _retryDelay = properties.getPropertyAsIntWithDefault(name + ".RetryDelay", 2000);
+            if(_retryDelay < 0)
+            {
+                _retryDelay = 0;
+            }
             _timer = IceInternal.Util.getInstance(lookup.ice_getCommunicator()).timer();
             _traceLevel = properties.getPropertyAsInt(name + ".Trace.Lookup");
             _instanceName = instanceName;
             _warned = false;
             _locator = lookup.ice_getCommunicator().getDefaultLocator();
             _voidLocator = voidLocator;
+            _pending = false;
             _pendingRetryCount = 0;
             _failureCount = 0;
             _warnOnce = true;
@@ -233,7 +246,7 @@ namespace IceLocatorDiscovery
             {
                 lock(this)
                 {
-                    while(!_locators.ContainsKey(instanceName) && _pendingRetryCount > 0)
+                    while(!_locators.ContainsKey(instanceName) && _pending)
                     {
                         Monitor.Wait(this, waitTime);
                     }
@@ -290,10 +303,11 @@ namespace IceLocatorDiscovery
                     return;
                 }
 
-                if(_pendingRetryCount > 0) // No need to retry, we found a locator
+                if(_pending) // No need to continue, we found a locator
                 {
                     _timer.cancel(this);
                     _pendingRetryCount = 0;
+                    _pending = false;
                 }
 
                 if(_traceLevel > 0)
@@ -396,8 +410,9 @@ namespace IceLocatorDiscovery
                         _pendingRequests.Add(request);
                     }
 
-                    if(_pendingRetryCount == 0) // No request in progress
+                    if(!_pending) // No request in progress
                     {
+                        _pending = true;
                         _pendingRetryCount = _retryCount;
                         _failureCount = 0;
                         try
@@ -448,6 +463,7 @@ namespace IceLocatorDiscovery
                             }
                             _pendingRequests.Clear();
                             _pendingRetryCount = 0;
+                            _pending = false;
                         }
                     }
                 }
@@ -458,14 +474,14 @@ namespace IceLocatorDiscovery
         {
             lock(this)
             {
-                if(++_failureCount == _lookups.Count && _pendingRetryCount > 0)
+                if(++_failureCount == _lookups.Count && _pending)
                 {
                     //
                     // All the lookup calls failed, cancel the timer and propagate the error to the requests.
                     //
                     _timer.cancel(this);
-
                     _pendingRetryCount = 0;
+                    _pending = false;
 
                     if(_warnOnce)
                     {
@@ -510,8 +526,15 @@ namespace IceLocatorDiscovery
         {
             lock(this)
             {
-                if(--_pendingRetryCount > 0)
+                if(!_pending)
                 {
+                    Debug.Assert(_pendingRequests.Count == 0);
+                    return; // Request failed
+                }
+
+                if(_pendingRetryCount > 0)
+                {
+                    --_pendingRetryCount;
                     try
                     {
                         if(_traceLevel > 1)
@@ -548,6 +571,9 @@ namespace IceLocatorDiscovery
                     _pendingRetryCount = 0;
                 }
 
+                Debug.Assert(_pendingRetryCount == 0);
+                _pending = false;
+
                 if(_traceLevel > 0)
                 {
                     StringBuilder s = new StringBuilder("locator lookup timed out:\nlookup = ");
@@ -589,6 +615,7 @@ namespace IceLocatorDiscovery
         private Ice.LocatorPrx _voidLocator;
         private Dictionary<string, Ice.LocatorPrx> _locators = new Dictionary<string, Ice.LocatorPrx>();
 
+        private bool _pending;
         private int _pendingRetryCount;
         private int _failureCount;
         private bool _warnOnce = true;
diff --git a/csharp/test/IceGrid/simple/AllTests.cs b/csharp/test/IceGrid/simple/AllTests.cs
index f52a30ebf39..4fd91284af4 100644
--- a/csharp/test/IceGrid/simple/AllTests.cs
+++ b/csharp/test/IceGrid/simple/AllTests.cs
@@ -160,6 +160,26 @@ public class AllTests : Test.AllTests
 
             initData.properties = communicator.getProperties().ice_clone_();
             initData.properties.setProperty("Ice.Default.Locator", "");
+            initData.properties.setProperty("IceLocatorDiscovery.RetryCount", "0");
+            initData.properties.setProperty("Ice.Plugin.IceLocatorDiscovery",
+                                            "IceLocatorDiscovery:IceLocatorDiscovery.PluginFactory");
+            initData.properties.setProperty("IceLocatorDiscovery.Lookup",
+                                             "udp -h " + multicast + " --interface unknown");
+            com = Ice.Util.initialize(initData);
+            test(com.getDefaultLocator() != null);
+            try
+            {
+                com.stringToProxy("test @ TestAdapter").ice_ping();
+                test(false);
+            }
+            catch(Ice.NoEndpointException)
+            {
+            }
+            com.destroy();
+
+            initData.properties = communicator.getProperties().ice_clone_();
+            initData.properties.setProperty("Ice.Default.Locator", "");
+            initData.properties.setProperty("IceLocatorDiscovery.RetryCount", "1");
             initData.properties.setProperty("Ice.Plugin.IceLocatorDiscovery",
                                             "IceLocatorDiscovery:IceLocatorDiscovery.PluginFactory");
             {
diff --git a/java-compat/src/IceLocatorDiscovery/src/main/java/IceLocatorDiscovery/PluginI.java b/java-compat/src/IceLocatorDiscovery/src/main/java/IceLocatorDiscovery/PluginI.java
index 8939c2b9d6d..a2386d2183a 100644
--- a/java-compat/src/IceLocatorDiscovery/src/main/java/IceLocatorDiscovery/PluginI.java
+++ b/java-compat/src/IceLocatorDiscovery/src/main/java/IceLocatorDiscovery/PluginI.java
@@ -142,14 +142,27 @@ class PluginI implements Plugin
         {
             _lookup = lookup;
             _timeout = properties.getPropertyAsIntWithDefault(name + ".Timeout", 300);
+            if(_timeout < 0)
+            {
+                _timeout = 300;
+            }
             _retryCount = properties.getPropertyAsIntWithDefault(name + ".RetryCount", 3);
+            if(_retryCount < 0)
+            {
+                _retryCount = 0;
+            }
             _retryDelay = properties.getPropertyAsIntWithDefault(name + ".RetryDelay", 2000);
+            if(_retryDelay < 0)
+            {
+                _retryDelay = 0;
+            }
             _timer = IceInternal.Util.getInstance(lookup.ice_getCommunicator()).timer();
             _traceLevel = properties.getPropertyAsInt(name + ".Trace.Lookup");
             _instanceName = instanceName;
             _warned = false;
             _locator = lookup.ice_getCommunicator().getDefaultLocator();
             _voidLocator = voidLocator;
+            _pending = false;
             _pendingRetryCount = 0;
             _failureCount = 0;
             _warnOnce = true;
@@ -234,7 +247,7 @@ class PluginI implements Plugin
                 {
                     synchronized(this)
                     {
-                        while(!_locators.containsKey(instanceName) && _pendingRetryCount > 0)
+                        while(!_locators.containsKey(instanceName) && _pending)
                         {
                             wait(waitTime);
                         }
@@ -293,12 +306,12 @@ class PluginI implements Plugin
                 return;
             }
 
-            if(_pendingRetryCount > 0) // No need to retry, we found a locator
+            if(_pending) // No need to continue, we found a locator
             {
                 _future.cancel(false);
                 _future = null;
-
                 _pendingRetryCount = 0;
+                _pending = false;
             }
 
             if(_traceLevel > 0)
@@ -392,8 +405,9 @@ class PluginI implements Plugin
                     _pendingRequests.add(request);
                 }
 
-                if(_pendingRetryCount == 0) // No request in progress
+                if(!_pending) // No request in progress
                 {
+                    _pending = true;
                     _pendingRetryCount = _retryCount;
                     _failureCount = 0;
                     try
@@ -447,6 +461,7 @@ class PluginI implements Plugin
                             req.invoke(_voidLocator);
                         }
                         _pendingRequests.clear();
+                        _pending = false;
                         _pendingRetryCount = 0;
                     }
                 }
@@ -456,15 +471,15 @@ class PluginI implements Plugin
         synchronized void
         exception(Ice.LocalException ex)
         {
-            if(++_failureCount == _lookups.size() && _pendingRetryCount > 0)
+            if(++_failureCount == _lookups.size() && _pending)
             {
                 //
                 // All the lookup calls failed, cancel the timer and propagate the error to the requests.
                 //
                 _future.cancel(false);
                 _future = null;
-
                 _pendingRetryCount = 0;
+                _pending = false;
 
                 if(_warnOnce)
                 {
@@ -511,8 +526,15 @@ class PluginI implements Plugin
             {
                 synchronized(LocatorI.this)
                 {
-                    if(--_pendingRetryCount > 0)
+                    if(!_pending)
+                    {
+                        assert(_pendingRequests.isEmpty());
+                        return; // Request failed
+                    }
+
+                    if(_pendingRetryCount > 0)
                     {
+                        --_pendingRetryCount;
                         try
                         {
                             if(_traceLevel > 1)
@@ -555,6 +577,9 @@ class PluginI implements Plugin
                         _pendingRetryCount = 0;
                     }
 
+                    assert(_pendingRetryCount == 0);
+                    _pending = false;
+
                     if(_traceLevel > 0)
                     {
                         StringBuilder s = new StringBuilder("locator lookup timed out:\nlookup = ");
@@ -586,12 +611,12 @@ class PluginI implements Plugin
 
         private final LookupPrx _lookup;
         private final java.util.Map<LookupPrx, LookupReplyPrx> _lookups = new java.util.HashMap<>();
-        private final int _timeout;
+        private int _timeout;
         private java.util.concurrent.Future<?> _future;
         private final java.util.concurrent.ScheduledExecutorService _timer;
         private final int _traceLevel;
-        private final int _retryCount;
-        private final int _retryDelay;
+        private int _retryCount;
+        private int _retryDelay;
 
         private String _instanceName;
         private boolean _warned;
@@ -599,6 +624,7 @@ class PluginI implements Plugin
         private Ice.LocatorPrx _voidLocator;
         private Map<String, Ice.LocatorPrx> _locators = new java.util.HashMap<>();
 
+        private boolean _pending;
         private int _pendingRetryCount;
         private int _failureCount;
         private boolean _warnOnce;
diff --git a/java-compat/test/src/main/java/test/IceGrid/simple/AllTests.java b/java-compat/test/src/main/java/test/IceGrid/simple/AllTests.java
index fdafdd3ff01..aef9a9f35a7 100644
--- a/java-compat/test/src/main/java/test/IceGrid/simple/AllTests.java
+++ b/java-compat/test/src/main/java/test/IceGrid/simple/AllTests.java
@@ -158,6 +158,27 @@ public class AllTests
             //
             properties = communicator.getProperties()._clone();
             properties.setProperty("Ice.Default.Locator", "");
+            properties.setProperty("IceLocatorDiscovery.RetryCount", "0");
+            properties.setProperty("Ice.Plugin.IceLocatorDiscovery",
+                                   "IceLocatorDiscovery.PluginFactory");
+            properties.setProperty("IceLocatorDiscovery.Lookup",
+                                   "udp -h " + multicast + " --interface unknown");
+            try(Ice.Communicator com = helper.initialize(properties))
+            {
+                test(com.getDefaultLocator() != null);
+                try
+                {
+                    com.stringToProxy("test @ TestAdapter").ice_ping();
+                    test(false);
+                }
+                catch(Ice.NoEndpointException ex)
+                {
+                }
+            }
+
+            properties = communicator.getProperties()._clone();
+            properties.setProperty("Ice.Default.Locator", "");
+            properties.setProperty("IceLocatorDiscovery.RetryCount", "1");
             properties.setProperty("Ice.Plugin.IceLocatorDiscovery",
                                    "IceLocatorDiscovery.PluginFactory");
             properties.setProperty("IceLocatorDiscovery.Lookup",
diff --git a/java/src/IceLocatorDiscovery/src/main/java/com/zeroc/IceLocatorDiscovery/PluginI.java b/java/src/IceLocatorDiscovery/src/main/java/com/zeroc/IceLocatorDiscovery/PluginI.java
index 18e0043493e..07c709c221f 100644
--- a/java/src/IceLocatorDiscovery/src/main/java/com/zeroc/IceLocatorDiscovery/PluginI.java
+++ b/java/src/IceLocatorDiscovery/src/main/java/com/zeroc/IceLocatorDiscovery/PluginI.java
@@ -138,8 +138,20 @@ class PluginI implements Plugin
         {
             _lookup = lookup;
             _timeout = properties.getPropertyAsIntWithDefault(name + ".Timeout", 300);
+            if(_timeout < 0)
+            {
+                _timeout = 300;
+            }
             _retryCount = properties.getPropertyAsIntWithDefault(name + ".RetryCount", 3);
+            if(_retryCount < 0)
+            {
+                _retryCount = 0;
+            }
             _retryDelay = properties.getPropertyAsIntWithDefault(name + ".RetryDelay", 2000);
+            if(_retryDelay < 0)
+            {
+                _retryDelay = 0;
+            }
             _timer = com.zeroc.IceInternal.Util.getInstance(lookup.ice_getCommunicator()).timer();
             _traceLevel = properties.getPropertyAsInt(name + ".Trace.Lookup");
             _instanceName = instanceName;
@@ -147,6 +159,7 @@ class PluginI implements Plugin
             _locator = lookup.ice_getCommunicator().getDefaultLocator();
             _voidLocator = voidLocator;
             _pendingRetryCount = 0;
+            _pending = false;
             _failureCount = 0;
             _warnOnce = true;
 
@@ -232,7 +245,7 @@ class PluginI implements Plugin
                 {
                     synchronized(this)
                     {
-                        while(!_locators.containsKey(instanceName) && _pendingRetryCount > 0)
+                        while(!_locators.containsKey(instanceName) && _pending)
                         {
                             wait(waitTime);
                         }
@@ -290,12 +303,12 @@ class PluginI implements Plugin
                 return;
             }
 
-            if(_pendingRetryCount > 0) // No need to retry, we found a locator
+            if(_pending) // No need to continue, we found a locator
             {
                 _future.cancel(false);
                 _future = null;
-
                 _pendingRetryCount = 0;
+                _pending = false;
             }
 
             if(_traceLevel > 0)
@@ -389,10 +402,11 @@ class PluginI implements Plugin
                     _pendingRequests.add(request);
                 }
 
-                if(_pendingRetryCount == 0) // No request in progress
+                if(!_pending) // No request in progress
                 {
-                    _failureCount = 0;
+                    _pending = true;
                     _pendingRetryCount = _retryCount;
+                    _failureCount = 0;
                     try
                     {
                         if(_traceLevel > 1)
@@ -436,6 +450,7 @@ class PluginI implements Plugin
                             req.invoke(_voidLocator);
                         }
                         _pendingRequests.clear();
+                        _pending = false;
                         _pendingRetryCount = 0;
                     }
                 }
@@ -444,15 +459,15 @@ class PluginI implements Plugin
 
         synchronized void exception(Throwable ex)
         {
-            if(++_failureCount == _lookups.size() && _pendingRetryCount > 0)
+            if(++_failureCount == _lookups.size() && _pending)
             {
                 //
                 // All the lookup calls failed, cancel the timer and propagate the error to the requests.
                 //
                 _future.cancel(false);
                 _future = null;
-
                 _pendingRetryCount = 0;
+                _pending = false;
 
                 if(_warnOnce)
                 {
@@ -499,8 +514,15 @@ class PluginI implements Plugin
             {
                 synchronized(LocatorI.this)
                 {
-                    if(--_pendingRetryCount > 0)
+                    if(!_pending)
                     {
+                        assert(_pendingRequests.isEmpty());
+                        return; // Request failed
+                    }
+
+                    if(_pendingRetryCount > 0)
+                    {
+                        --_pendingRetryCount;
                         try
                         {
                             if(_traceLevel > 1)
@@ -535,6 +557,9 @@ class PluginI implements Plugin
                         _pendingRetryCount = 0;
                     }
 
+                    assert(_pendingRetryCount == 0);
+                    _pending = false;
+
                     if(_traceLevel > 0)
                     {
                         StringBuilder s = new StringBuilder("locator lookup timed out:\nlookup = ");
@@ -566,12 +591,12 @@ class PluginI implements Plugin
 
         private final LookupPrx _lookup;
         private final Map<LookupPrx, LookupReplyPrx> _lookups = new java.util.HashMap<>();
-        private final int _timeout;
+        private int _timeout;
         private java.util.concurrent.Future<?> _future;
         private final java.util.concurrent.ScheduledExecutorService _timer;
         private final int _traceLevel;
-        private final int _retryCount;
-        private final int _retryDelay;
+        private int _retryCount;
+        private int _retryDelay;
 
         private String _instanceName;
         private boolean _warned;
@@ -579,6 +604,7 @@ class PluginI implements Plugin
         private com.zeroc.Ice.LocatorPrx _voidLocator;
         private Map<String, com.zeroc.Ice.LocatorPrx> _locators = new HashMap<>();
 
+        private boolean _pending;
         private int _pendingRetryCount;
         private int _failureCount;
         private boolean _warnOnce;
diff --git a/java/test/src/main/java/test/IceGrid/simple/AllTests.java b/java/test/src/main/java/test/IceGrid/simple/AllTests.java
index 9c53a754803..1132be3b311 100644
--- a/java/test/src/main/java/test/IceGrid/simple/AllTests.java
+++ b/java/test/src/main/java/test/IceGrid/simple/AllTests.java
@@ -173,6 +173,26 @@ public class AllTests
 
             initData.properties = communicator.getProperties()._clone();
             initData.properties.setProperty("Ice.Default.Locator", "");
+            initData.properties.setProperty("IceLocatorDiscovery.RetryCount", "0");
+            initData.properties.setProperty("Ice.Plugin.IceLocatorDiscovery",
+                                            "com.zeroc.IceLocatorDiscovery.PluginFactory");
+            initData.properties.setProperty("IceLocatorDiscovery.Lookup",
+                                             "udp -h " + multicast + " --interface unknown");
+            comm = com.zeroc.Ice.Util.initialize(initData);
+            test(comm.getDefaultLocator() != null);
+            try
+            {
+                comm.stringToProxy("test @ TestAdapter").ice_ping();
+                test(false);
+            }
+            catch(com.zeroc.Ice.NoEndpointException ex)
+            {
+            }
+            comm.destroy();
+
+            initData.properties = communicator.getProperties()._clone();
+            initData.properties.setProperty("Ice.Default.Locator", "");
+            initData.properties.setProperty("IceLocatorDiscovery.RetryCount", "1");
             initData.properties.setProperty("Ice.Plugin.IceLocatorDiscovery",
                                             "com.zeroc.IceLocatorDiscovery.PluginFactory");
             {