SeleniumHQ
diff --git a/‎java/client/src/org/openqa/selenium/remote/DriverCommand.java‎
Lines changed: 20 additions & 2 deletions b/‎java/client/src/org/openqa/selenium/remote/DriverCommand.java‎
Lines changed: 20 additions & 2 deletions
diff --git a/‎java/client/src/org/openqa/selenium/remote/RemoteWebDriver.java‎
Lines changed: 3 additions & 2 deletions b/‎java/client/src/org/openqa/selenium/remote/RemoteWebDriver.java‎
Lines changed: 3 additions & 2 deletions
@@ -18,20 +18,21 @@
 package org.openqa.selenium.remote;
 
 import com.google.common.collect.ImmutableMap;
-
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.Cookie;
 import org.openqa.selenium.Dimension;
 import org.openqa.selenium.Point;
 import org.openqa.selenium.WindowType;
 import org.openqa.selenium.interactions.Sequence;
+import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.print.PrintOptions;
 
 import java.time.Duration;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
 
 /**
  * An empty interface defining constants for the standard commands defined in the WebDriver JSON
@@ -44,7 +45,24 @@ public interface DriverCommand {
   String GET_CAPABILITIES = "getCapabilities";
   String NEW_SESSION = "newSession";
   static CommandPayload NEW_SESSION(Capabilities capabilities) {
-    return new CommandPayload(NEW_SESSION, ImmutableMap.of("desiredCapabilities", capabilities));
+    Require.nonNull("Capabilities", capabilities);
+    return new CommandPayload(
+      NEW_SESSION,
+      ImmutableMap.of(
+        "capabilities", CapabilitiesUtils.makeW3CSafe(capabilities).collect(Collectors.toSet()),
+        "desiredCapabilities", capabilities));
+  }
+  static CommandPayload NEW_SESSION(Collection<Capabilities> capabilities) {
+    Require.nonNull("Capabilities", capabilities);
+    if (capabilities.isEmpty()) {
+      throw new IllegalArgumentException("Capabilities for new session must not be empty");
+    }
+
+    return new CommandPayload(
+      NEW_SESSION,
+      ImmutableMap.of(
+        "capabilities", capabilities.stream().flatMap(CapabilitiesUtils::makeW3CSafe).collect(Collectors.toSet()),
+        "desiredCapabilities", capabilities.iterator().next()));
   }
 
   String STATUS = "status";
 
@@ -88,6 +88,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import static java.util.Collections.singleton;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.openqa.selenium.remote.CapabilityType.LOGGING_PREFS;
 import static org.openqa.selenium.remote.CapabilityType.PLATFORM;
@@ -248,7 +249,7 @@ protected void setSessionId(String opaqueKey) {
   }
 
   protected void startSession(Capabilities capabilities) {
-    Response response = execute(DriverCommand.NEW_SESSION(capabilities));
+    Response response = execute(DriverCommand.NEW_SESSION(singleton(capabilities)));
 
     if (response == null) {
       throw new SessionNotCreatedException(
@@ -269,7 +270,7 @@ protected void startSession(Capabilities capabilities) {
         response.toString());
     }
 
-    Map<String, Object> rawCapabilities = (Map<String, Object>) responseValue;
+    @SuppressWarnings("unchecked") Map<String, Object> rawCapabilities = (Map<String, Object>) responseValue;
     MutableCapabilities returnedCapabilities = new MutableCapabilities(rawCapabilities);
     String platformString = (String) rawCapabilities.getOrDefault(
       PLATFORM,