diff --git a/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXApplication.java b/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXApplication.java
index c21bfbc60e6..e8ee8be0bfe 100644
--- a/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXApplication.java
+++ b/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXApplication.java
@@ -15,9 +15,11 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.math.BigDecimal;
+import java.net.BindException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.net.URLConnection;
 import java.net.URLDecoder;
 import java.util.ArrayList;
 import java.util.Enumeration;
@@ -44,6 +46,7 @@
 
 import com.webobjects.appserver.WOAction;
 import com.webobjects.appserver.WOActionResults;
+import com.webobjects.appserver.WOAdaptor;
 import com.webobjects.appserver.WOApplication;
 import com.webobjects.appserver.WOComponent;
 import com.webobjects.appserver.WOContext;
@@ -98,6 +101,7 @@
 import er.extensions.foundation.ERXArrayUtilities;
 import er.extensions.foundation.ERXCompressionUtilities;
 import er.extensions.foundation.ERXConfigurationManager;
+import er.extensions.foundation.ERXExceptionUtilities;
 import er.extensions.foundation.ERXPatcher;
 import er.extensions.foundation.ERXProperties;
 import er.extensions.foundation.ERXRuntimeUtilities;
@@ -150,6 +154,7 @@
  * @property er.extensions.ERXApplication.useEditingContextUnlocker
  * @property er.extensions.ERXApplication.useSessionStoreDeadlockDetection
  * @property er.extensions.ERXComponentActionRedirector.enabled
+ * @property er.extensions.ERXApplication.allowMultipleDevInstances
  */
 public abstract class ERXApplication extends ERXAjaxApplication implements ERXGracefulShutdown.GracefulApplication {
 
@@ -821,6 +826,49 @@ public static void main(String argv[], Class applicationClass) {
 		WOApplication.main(argv, applicationClass);
 	}
 
+	/**
+	 * <p>Terminates a different instance of the same application that may already be running.<br>
+	 * Only in dev mode.</p>
+	 * <p>Set the property "er.extensions.ERXApplication.allowMultipleDevInstances" to "true" if
+	 * you need to run multiple instances in dev mode.</p>
+	 * 
+	 * @return true if a previously running instance was stopped.
+	 */
+	private static boolean stopPreviousDevInstance() {
+		if (!isDevelopmentModeSafe() || 
+				ERXProperties.booleanForKeyWithDefault("er.extensions.ERXApplication.allowMultipleDevInstances", false)) {
+			return false;
+		}
+		
+		String appUrl;
+		if (!(application().wasMainInvoked())) {
+			return false;
+		} else if (application().isDirectConnectEnabled()) {
+			appUrl = application().cgiAdaptorURL().replace("/cgi", ":" + application().port() + "/cgi");
+			appUrl += "/" + application().name() + ".woa";
+		} else {
+			appUrl = application().cgiAdaptorURL() + "/" + application().name() + ".woa/-" + application().port();
+		}
+		
+		URL url;
+		try {
+			appUrl = appUrl + "/" + application().directActionRequestHandlerKey() + "/stop";
+			url = new URL(appUrl);
+
+			log.debug("Stopping previously running instance of " + application().name());
+			
+			URLConnection connection = url.openConnection();
+			connection.getContent();
+			
+			Thread.sleep(2000); // really only necessary for direct connect mode
+			
+			return true;
+		} catch (Throwable e) {
+			e.printStackTrace();
+		}
+		return false;
+	}
+	
 	/**
 	 * Utility class to track down duplicate items in the class path. Reports
 	 * duplicate packages and packages that are present in different versions.
@@ -2617,6 +2665,19 @@ public NSArray<NSDictionary<String, Object>> additionalAdaptors() {
 		return additionalAdaptors;
 	}
 
+	@Override
+	public WOAdaptor adaptorWithName(String aClassName, NSDictionary<String, Object> anArgsDictionary) {
+		try {
+			return super.adaptorWithName(aClassName, anArgsDictionary);
+		} catch (NSForwardException e) {
+			Throwable rootCause = ERXExceptionUtilities.getMeaningfulThrowable(e);
+			if ((rootCause instanceof BindException) && stopPreviousDevInstance()) {
+				return super.adaptorWithName(aClassName, anArgsDictionary);
+			}
+			throw e;
+		}
+	}
+	
 	protected void _debugValueForDeclarationNamed(WOComponent component, String verb, String aDeclarationName, String aDeclarationType, String aBindingName, String anAssociationDescription, Object aValue) {
 		if (aValue instanceof String) {
 			StringBuffer stringbuffer = new StringBuffer(((String) aValue).length() + 2);
diff --git a/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXDirectAction.java b/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXDirectAction.java
index 14b5f41edfb..32cb2bf3296 100644
--- a/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXDirectAction.java
+++ b/Frameworks/Core/ERExtensions/Sources/er/extensions/appserver/ERXDirectAction.java
@@ -503,4 +503,18 @@ public <T extends WOComponent> T pageWithName(Class<T> componentClass) {
       return (T) super.pageWithName(componentClass.getName());
     }
 
+	public WOActionResults stopAction() {
+    	WOResponse response = new WOResponse();
+    	response.setHeader("text/plain", "Content-Type");
+
+		if (ERXApplication.isDevelopmentModeSafe()) {
+	    	WOApplication.application().terminate();
+			response.setContent("OK");
+		} else {
+			response.setStatus(401);
+		}
+		
+    	return response;
+	}
+	
 }