Changed activator to work with multiple clients but always look for a…

… free port starting from the default port.

net.sf.py4j.defaultserver/src/net/sf/py4j/defaultserver/DefaultServerActivator.java

@@ -42,23 +42,28 @@ public void start(BundleContext bundleContext) throws Exception {
 		final boolean enabled = getPreferenceStore().getBoolean(PreferenceConstants.PREF_PY4J_ACTIVE);
 		boolean override = Boolean.getBoolean(PreferenceConstants.PREF_PY4J_ACTIVE); // They can override the default using -DPREF_PY4J_ACTIVE=...
 		if (!enabled && !override) return;
+
+		// We override any port setting because we record the autogenerated one.
+		getPreferenceStore().setValue(PreferenceConstants.PREF_DEFAULT_PORT, GatewayServer.DEFAULT_PORT);
+		getPreferenceStore().setValue(PreferenceConstants.PREF_DEFAULT_CALLBACK_PORT, GatewayServer.DEFAULT_PYTHON_PORT);
 
+		// Now we look for a free port and record the one we end up with if we change it (multiple clients are possible!)
 		int defaultPort = getPreferenceStore().getInt(PreferenceConstants.PREF_DEFAULT_PORT);
 		if (defaultPort<1) defaultPort = GatewayServer.DEFAULT_PORT;
 
 		// We look for a free port and change the preference if the port is not free.
 		if (!isPortFree(defaultPort)) {
-			defaultPort = getFreePort(defaultPort);
+			defaultPort = getFreePort(defaultPort, 2);
 			getPreferenceStore().setValue(PreferenceConstants.PREF_DEFAULT_PORT, defaultPort);
+			getPreferenceStore().setValue(PreferenceConstants.PREF_DEFAULT_CALLBACK_PORT, getFreePort(defaultPort+1, 1));
 		}
 
-
 		int defaultCallBackPort = getPreferenceStore().getInt(PreferenceConstants.PREF_DEFAULT_CALLBACK_PORT);
 		if (defaultCallBackPort<1) defaultCallBackPort = GatewayServer.DEFAULT_PYTHON_PORT;
 
 		// We look for a free port and change the preference if the port is not free.
 		if (!isPortFree(defaultCallBackPort)) {
-			defaultCallBackPort = getFreePort(defaultCallBackPort);
+			defaultCallBackPort = getFreePort(defaultCallBackPort, 2);
 			getPreferenceStore().setValue(PreferenceConstants.PREF_DEFAULT_CALLBACK_PORT, defaultCallBackPort);
 		}
 
@@ -106,11 +111,11 @@ public void start(BundleContext bundleContext) throws Exception {
 	 * @param startPort
 	 * @return
 	 */
-	public static int getFreePort(final int startPort) {
+	public static int getFreePort(final int startPort, int inc) {
 
 		int port = startPort;
 		while (!isPortFree(port))
-			port++;
+			port+=inc;
 
 		return port;
 	}