From bf15697220c1d5c6d4dda385c5a476663a0d6b3a Mon Sep 17 00:00:00 2001
From: zidanmp <zidanmp786@gmail.com>
Date: Sat, 12 Jul 2025 16:13:52 +0530
Subject: [PATCH] fix(firefox): handle null args in FirefoxOptions.merge()
 (#15991)

---
 java/src/org/openqa/selenium/firefox/FirefoxOptions.java | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/java/src/org/openqa/selenium/firefox/FirefoxOptions.java b/java/src/org/openqa/selenium/firefox/FirefoxOptions.java
index 4737d8cab7e99..f5a714bb15f9e 100644
--- a/java/src/org/openqa/selenium/firefox/FirefoxOptions.java
+++ b/java/src/org/openqa/selenium/firefox/FirefoxOptions.java
@@ -305,7 +305,8 @@ public FirefoxOptions merge(Capabilities capabilities) {
         List<String> arguments = (List<String>) (capabilities.getCapability(("args")));
         arguments.forEach(
             arg -> {
-              if (!((List<String>) newInstance.firefoxOptions.get(Keys.ARGS.key())).contains(arg)) {
+              List<String> existingArgs = (List<String>) newInstance.firefoxOptions.get(Keys.ARGS.key());
+              if (existingArgs == null || !existingArgs.contains(arg)) {
                 newInstance.addArguments(arg);
               }
             });
@@ -367,7 +368,8 @@ public FirefoxOptions merge(Capabilities capabilities) {
 
         arguments.forEach(
             arg -> {
-              if (!((List<String>) newInstance.firefoxOptions.get(Keys.ARGS.key())).contains(arg)) {
+              List<String> existingArgs = (List<String>) newInstance.firefoxOptions.get(Keys.ARGS.key());
+              if (existingArgs == null || !existingArgs.contains(arg)) {
                 newInstance.addArguments(arg);
               }
             });