diff --git a/java/src/org/openqa/selenium/Capabilities.java b/java/src/org/openqa/selenium/Capabilities.java
index 683e5e4e41b7d..053cdd971fc75 100644
--- a/java/src/org/openqa/selenium/Capabilities.java
+++ b/java/src/org/openqa/selenium/Capabilities.java
@@ -24,15 +24,18 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Stream;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 /** Describes a series of key/value pairs that encapsulate aspects of a browser. */
+@NullMarked
 public interface Capabilities extends Serializable {
 
   default String getBrowserName() {
     return String.valueOf(Optional.ofNullable(getCapability("browserName")).orElse(""));
   }
 
-  default Platform getPlatformName() {
+  default @Nullable Platform getPlatformName() {
     return Stream.of("platformName")
         .map(this::getCapability)
         .filter(Objects::nonNull)
@@ -67,7 +70,7 @@ default String getBrowserVersion() {
    * @return The value, or null if not set.
    * @see org.openqa.selenium.remote.CapabilityType
    */
-  Object getCapability(String capabilityName);
+  @Nullable Object getCapability(String capabilityName);
 
   /**
    * @param capabilityName The capability to check.
diff --git a/java/src/org/openqa/selenium/HasCapabilities.java b/java/src/org/openqa/selenium/HasCapabilities.java
index bd8f9ef44a52b..af0cf7213f236 100644
--- a/java/src/org/openqa/selenium/HasCapabilities.java
+++ b/java/src/org/openqa/selenium/HasCapabilities.java
@@ -17,10 +17,13 @@
 
 package org.openqa.selenium;
 
+import org.jspecify.annotations.NullMarked;
+
 /**
  * Used by classes to indicate that they can describe the {@link org.openqa.selenium.Capabilities}
  * they possess. This can be used for run-time detection of features.
  */
+@NullMarked
 public interface HasCapabilities {
   /**
    * @return The capabilities of the current driver.
diff --git a/java/src/org/openqa/selenium/ImmutableCapabilities.java b/java/src/org/openqa/selenium/ImmutableCapabilities.java
index ee800049fc345..a617134fca3cb 100644
--- a/java/src/org/openqa/selenium/ImmutableCapabilities.java
+++ b/java/src/org/openqa/selenium/ImmutableCapabilities.java
@@ -22,8 +22,11 @@
 import java.util.Collections;
 import java.util.Map;
 import java.util.TreeMap;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.internal.Require;
 
+@NullMarked
 public class ImmutableCapabilities implements Capabilities {
 
   private final Map<String, Object> delegate;
@@ -145,10 +148,9 @@ public ImmutableCapabilities(Map<?, ?> capabilities) {
     capabilities.forEach(
         (key, value) -> {
           Require.argument("Capability key", key).instanceOf(String.class);
-          Object v = capabilities.get(key);
           Require.nonNull("Capability value", value);
 
-          setCapability(delegate, (String) key, v);
+          setCapability(delegate, (String) key, value);
         });
 
     this.delegate = Collections.unmodifiableMap(delegate);
@@ -156,7 +158,7 @@ public ImmutableCapabilities(Map<?, ?> capabilities) {
   }
 
   @Override
-  public Object getCapability(String capabilityName) {
+  public @Nullable Object getCapability(String capabilityName) {
     Require.nonNull("Capability name", capabilityName);
     return delegate.get(capabilityName);
   }
@@ -172,7 +174,7 @@ public int hashCode() {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (!(o instanceof Capabilities)) {
       return false;
     }
diff --git a/java/src/org/openqa/selenium/MutableCapabilities.java b/java/src/org/openqa/selenium/MutableCapabilities.java
index 16c56b5536d60..143c32680149b 100644
--- a/java/src/org/openqa/selenium/MutableCapabilities.java
+++ b/java/src/org/openqa/selenium/MutableCapabilities.java
@@ -22,8 +22,11 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.internal.Require;
 
+@NullMarked
 public class MutableCapabilities implements Capabilities {
 
   private static final Set<String> OPTION_KEYS;
@@ -81,7 +84,7 @@ public void setCapability(String capabilityName, Platform value) {
     setCapability(capabilityName, (Object) value);
   }
 
-  public void setCapability(String key, Object value) {
+  public void setCapability(String key, @Nullable Object value) {
     Require.nonNull("Capability name", key);
 
     // We have to special-case some keys and values because of the popular idiom of calling
@@ -107,7 +110,7 @@ public Map<String, Object> asMap() {
   }
 
   @Override
-  public Object getCapability(String capabilityName) {
+  public @Nullable Object getCapability(String capabilityName) {
     return caps.get(capabilityName);
   }
 
@@ -126,7 +129,7 @@ public int hashCode() {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (!(o instanceof Capabilities)) {
       return false;
     }
diff --git a/java/src/org/openqa/selenium/PersistentCapabilities.java b/java/src/org/openqa/selenium/PersistentCapabilities.java
index 8da7482bf6e4b..f5d52cec5f079 100644
--- a/java/src/org/openqa/selenium/PersistentCapabilities.java
+++ b/java/src/org/openqa/selenium/PersistentCapabilities.java
@@ -22,8 +22,11 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.internal.Require;
 
+@NullMarked
 public class PersistentCapabilities implements Capabilities {
 
   private final ImmutableCapabilities caps;
@@ -60,7 +63,7 @@ public Map<String, Object> asMap() {
   }
 
   @Override
-  public Object getCapability(String capabilityName) {
+  public @Nullable Object getCapability(String capabilityName) {
     Require.nonNull("Capability name", capabilityName);
     Object capability = overrides.getCapability(capabilityName);
     if (capability != null) {
@@ -93,7 +96,7 @@ public int hashCode() {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (!(o instanceof Capabilities)) {
       return false;
     }