[java] fix some nullability warnings

java/src/org/openqa/selenium/events/Event.java

@@ -20,6 +20,7 @@
 import java.util.Objects;
 import java.util.StringJoiner;
 import java.util.UUID;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
 import org.openqa.selenium.json.JsonOutput;
@@ -31,11 +32,11 @@ public class Event {
   private final EventName eventName;
   private final String data;
 
-  public Event(EventName eventName, Object data) {
+  public Event(EventName eventName, @Nullable Object data) {
     this(UUID.randomUUID(), eventName, data);
   }
 
-  public Event(UUID id, EventName eventName, Object data) {
+  public Event(UUID id, EventName eventName, @Nullable Object data) {
     this.id = Require.nonNull("Message id", id);
     this.eventName = Require.nonNull("Event type", eventName);
 

java/src/org/openqa/selenium/grid/Bootstrap.java

@@ -27,6 +27,9 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.ArrayList;
@@ -90,16 +93,19 @@ private static ClassLoader createExtendedClassLoader(String ext) {
         continue;
       }
 
-      if (file.isDirectory()) {
-        File[] files = file.listFiles();
-        if (files == null) {
-          LOG.warning("Cannot list files in directory: " + file);
-        } else {
-          for (File subdirFile : files) {
+      Path dir = file.toPath();
+
+      if (Files.isDirectory(dir)) {
+        try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
+          for (Path path : stream) {
+            File subdirFile = path.toFile();
             if (subdirFile.isFile() && subdirFile.getName().endsWith(".jar")) {
               jars.add(subdirFile);
             }
           }
+        } catch (IOException e) {
+          LOG.warning(
+              () -> String.format("Cannot list files in directory: %s due to: %s", file, e));
         }
       } else {
         jars.add(file);

java/src/org/openqa/selenium/grid/distributor/remote/RemoteDistributor.java

@@ -75,7 +75,7 @@ public RemoteDistributor add(Node node) {
 
     HttpResponse response = client.with(addSecret).execute(request);
 
-    Values.get(response, Void.class);
+    Values.parse(response);
 
     LOG.info(String.format("Added node %s.", node.getId()));
 
@@ -91,7 +91,7 @@ public boolean drain(NodeId nodeId) {
 
     HttpResponse response = client.with(addSecret).execute(request);
 
-    return Values.get(response, Boolean.class);
+    return Values.parseBoolean(response);
   }
 
   @Override
@@ -102,7 +102,7 @@ public void remove(NodeId nodeId) {
 
     HttpResponse response = client.with(addSecret).execute(request);
 
-    Values.get(response, Void.class);
+    Values.parse(response);
   }
 
   @Override
@@ -112,7 +112,7 @@ public DistributorStatus getStatus() {
 
     HttpResponse response = client.execute(request);
 
-    return Values.get(response, DistributorStatus.class);
+    return Values.parse(response, DistributorStatus.class);
   }
 
   @Override
@@ -125,7 +125,7 @@ public Either<SessionNotCreatedException, CreateSessionResponse> newSession(
     HttpResponse res = client.execute(req);
 
     if (res.isSuccessful()) {
-      return Either.right(Values.get(res, CreateSessionResponse.class));
+      return Either.right(Values.parse(res, CreateSessionResponse.class));
     } else {
       return Either.left(Values.get(res, SessionNotCreatedException.class));
     }

java/src/org/openqa/selenium/grid/node/remote/RemoteNode.java

@@ -207,7 +207,7 @@ public boolean isSessionOwner(SessionId id) {
 
     HttpResponse res = client.with(addSecret).execute(req);
 
-    return Boolean.TRUE.equals(Values.get(res, Boolean.class));
+    return Values.parseBoolean(res);
   }
 
   @Override
@@ -219,7 +219,7 @@ public boolean tryAcquireConnection(SessionId id) {
 
     HttpResponse res = client.with(addSecret).execute(req);
 
-    return Boolean.TRUE.equals(Values.get(res, Boolean.class));
+    return Values.parseBoolean(res);
   }
 
   @Override
@@ -231,7 +231,7 @@ public void releaseConnection(SessionId id) {
 
     HttpResponse res = client.with(addSecret).execute(req);
 
-    Values.get(res, Void.class);
+    Values.parse(res);
   }
 
   @Override
@@ -243,7 +243,7 @@ public Session getSession(SessionId id) throws NoSuchSessionException {
 
     HttpResponse res = client.with(addSecret).execute(req);
 
-    return Require.nonNull("Session", Values.get(res, Session.class));
+    return Values.parse(res, Session.class);
   }
 
   @Override
@@ -274,7 +274,7 @@ public void stop(SessionId id) throws NoSuchSessionException {
 
     HttpResponse res = client.with(addSecret).execute(req);
 
-    Values.get(res, Void.class);
+    Values.parse(res);
   }
 
   @Override

java/src/org/openqa/selenium/grid/sessionmap/remote/RemoteSessionMap.java

@@ -24,7 +24,6 @@
 import static org.openqa.selenium.remote.http.HttpMethod.POST;
 
 import java.io.UncheckedIOException;
-import java.lang.reflect.Type;
 import java.net.MalformedURLException;
 import java.net.URI;
 import org.jspecify.annotations.Nullable;
@@ -114,7 +113,7 @@ public void remove(SessionId id) {
   }
 
   @Nullable
-  private <T> T makeRequest(HttpRequest request, Type typeOfT) {
+  private <T> T makeRequest(HttpRequest request, Class<T> typeOfT) {
     HttpTracing.inject(tracer, tracer.getCurrentContext(), request);
 
     HttpResponse response = client.execute(request);

java/src/org/openqa/selenium/grid/sessionqueue/remote/RemoteNewSessionQueue.java

@@ -121,7 +121,7 @@ public boolean retryAddToQueue(SessionRequest request) {
     HttpTracing.inject(tracer, tracer.getCurrentContext(), upstream);
     upstream.setContent(Contents.asJson(request));
     HttpResponse response = client.with(addSecret).execute(upstream);
-    return Values.get(response, Boolean.class);
+    return Values.parseBoolean(response);
   }
 
   @Override
@@ -156,7 +156,7 @@ public List<SessionRequest> getNextAvailable(Map<Capabilities, Long> stereotypes
     HttpTracing.inject(tracer, tracer.getCurrentContext(), upstream);
     HttpResponse response = client.with(addSecret).execute(upstream);
 
-    return Values.get(response, SESSION_REQUEST_TYPE);
+    return Require.nonNull("Next session request", Values.get(response, SESSION_REQUEST_TYPE));
   }
 
   @Override
@@ -178,7 +178,7 @@ public boolean complete(
 
     HttpTracing.inject(tracer, tracer.getCurrentContext(), upstream);
     HttpResponse response = client.with(addSecret).execute(upstream);
-    return Values.get(response, Boolean.class);
+    return Values.parseBoolean(response);
   }
 
   @Override
@@ -187,7 +187,7 @@ public int clearQueue() {
     HttpTracing.inject(tracer, tracer.getCurrentContext(), upstream);
     HttpResponse response = client.with(addSecret).execute(upstream);
 
-    return Values.get(response, Integer.class);
+    return Values.parse(response, Integer.class);
   }
 
   @Override
@@ -196,7 +196,7 @@ public List<SessionRequestCapability> getQueueContents() {
     HttpTracing.inject(tracer, tracer.getCurrentContext(), upstream);
     HttpResponse response = client.execute(upstream);
 
-    return Values.get(response, QUEUE_CONTENTS_TYPE);
+    return Require.nonNull("Queue contents", Values.get(response, QUEUE_CONTENTS_TYPE));
   }
 
   @Override

java/src/org/openqa/selenium/grid/web/Values.java

@@ -26,6 +26,8 @@
 import java.io.Reader;
 import java.io.UncheckedIOException;
 import java.lang.reflect.Type;
+import org.jspecify.annotations.Nullable;
+import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
 import org.openqa.selenium.json.JsonInput;
 import org.openqa.selenium.remote.ErrorCodec;
@@ -36,6 +38,19 @@ public class Values {
   private static final Json JSON = new Json();
   private static final ErrorCodec ERRORS = ErrorCodec.createDefault();
 
+  public static <T> T parse(HttpResponse response, Class<T> classOfT) {
+    return Require.nonNull(classOfT.getSimpleName(), get(response, classOfT));
+  }
+
+  public static void parse(HttpResponse response) {
+    get(response, Void.class);
+  }
+
+  public static boolean parseBoolean(HttpResponse response) {
+    return Boolean.TRUE.equals(get(response, Boolean.class));
+  }
+
+  @Nullable
   public static <T> T get(HttpResponse response, Type typeOfT) {
     try (Reader reader = reader(response);
         JsonInput input = JSON.newInput(reader)) {

java/src/org/openqa/selenium/io/Zip.java

@@ -26,6 +26,9 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.attribute.FileTime;
 import java.util.Base64;
 import java.util.logging.Level;
@@ -54,12 +57,15 @@ public static String zip(File input) throws IOException {
 
   private static void addToZip(String basePath, ZipOutputStream zos, File toAdd)
       throws IOException {
-    if (toAdd.isDirectory()) {
-      File[] files = toAdd.listFiles();
-      if (files != null) {
-        for (File file : files) {
-          addToZip(basePath, zos, file);
+    Path dirPath = toAdd.toPath();
+
+    if (Files.isDirectory(dirPath)) {
+      try (DirectoryStream<Path> stream = Files.newDirectoryStream(dirPath)) {
+        for (Path path : stream) {
+          addToZip(basePath, zos, path.toFile());
         }
+      } catch (IOException e) {
+        LOG.warning(() -> String.format("Failed to read directory %s for zipping: %s", toAdd, e));
       }
     } else {
       try (FileInputStream fis = new FileInputStream(toAdd)) {

java/src/org/openqa/selenium/remote/codec/AbstractHttpCommandCodec.java

@@ -322,7 +322,10 @@ protected void defineCommand(String name, CommandSpec spec) {
   }
 
   private String buildUri(
-      String commandName, SessionId sessionId, Map<String, ?> parameters, CommandSpec spec) {
+      String commandName,
+      @Nullable SessionId sessionId,
+      Map<String, ?> parameters,
+      CommandSpec spec) {
     StringBuilder builder = new StringBuilder();
     for (String part : spec.pathSegments) {
       if (part.isEmpty()) {
@@ -340,10 +343,12 @@ private String buildUri(
   }
 
   private String getParameter(
-      String parameterName, String commandName, SessionId sessionId, Map<String, ?> parameters) {
+      String parameterName,
+      String commandName,
+      @Nullable SessionId sessionId,
+      Map<String, ?> parameters) {
     if ("sessionId".equals(parameterName)) {
-      Require.argument("Session id", sessionId)
-          .nonNull("Session ID may not be null for command %s", commandName);
+      Require.nonNull("Session id", sessionId, "may not be null for command %s", commandName);
       return sessionId.toString();
     }
 

java/test/org/openqa/selenium/AlertsTest.java

@@ -20,6 +20,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.openqa.selenium.WaitingConditions.newWindowIsOpened;
 import static org.openqa.selenium.support.ui.ExpectedConditions.alertIsPresent;
 import static org.openqa.selenium.support.ui.ExpectedConditions.presenceOfElementLocated;
@@ -117,8 +118,10 @@ void testShouldThrowIllegalArgumentExceptionWhenKeysNull() {
     driver.findElement(By.id("alert")).click();
     Alert alert = wait.until(alertIsPresent());
 
-    assertThatExceptionOfType(IllegalArgumentException.class)
-        .isThrownBy(() -> alert.sendKeys(null));
+    //noinspection DataFlowIssue
+    assertThatThrownBy(() -> alert.sendKeys(null))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Keys to send should be a not null CharSequence");
   }
 
   @Test

java/test/org/openqa/selenium/ClickScrollingTest.java

@@ -123,7 +123,7 @@ void testShouldNotScrollOverflowElementsWhichAreVisible() {
     WebElement list = driver.findElement(By.tagName("ul"));
     WebElement item = list.findElement(By.id("desired"));
     item.click();
-    long yOffset =
+    Long yOffset =
         (Long) ((JavascriptExecutor) driver).executeScript("return arguments[0].scrollTop;", list);
     assertThat(yOffset).describedAs("Should not have scrolled").isZero();
   }
@@ -235,7 +235,7 @@ void testShouldNotScrollWhenGettingElementSize() {
     assertThat(getScrollTop()).isEqualTo(scrollTop);
   }
 
-  private long getScrollTop() {
+  private Long getScrollTop() {
     wait.until(presenceOfElementLocated(By.tagName("body")));
     return (Long) ((JavascriptExecutor) driver).executeScript("return document.body.scrollTop;");
   }

java/test/org/openqa/selenium/chrome/ChromeDriverFunctionalTest.java

@@ -39,6 +39,7 @@
 import org.openqa.selenium.chromium.HasCdp;
 import org.openqa.selenium.chromium.HasNetworkConditions;
 import org.openqa.selenium.chromium.HasPermissions;
+import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.net.PortProber;
 import org.openqa.selenium.remote.RemoteWebDriverBuilder;
 import org.openqa.selenium.remote.http.ClientConfig;
@@ -126,7 +127,7 @@ public String checkPermission(WebDriver driver, String permission) {
                         + "name: arguments[0]"
                         + "}));",
                     permission);
-    return result.get("state").toString();
+    return Require.nonNull("Result", result).get("state").toString();
   }
 
   @Test

java/test/org/openqa/selenium/environment/webserver/AppServerTestBase.java

@@ -17,6 +17,7 @@
 
 package org.openqa.selenium.environment.webserver;
 
+import static java.util.Objects.requireNonNull;
 import static java.util.stream.StreamSupport.stream;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.openqa.selenium.By.id;
@@ -46,17 +47,19 @@
 public abstract class AppServerTestBase {
   private static final String APPCACHE_MIME_TYPE = "text/cache-manifest";
   private AppServer server;
-  private static @Nullable WebDriver driver = null;
+  private static @Nullable WebDriver cachedDriver = null;
+  private WebDriver driver;
 
   @BeforeAll
   public static void startDriver() {
-    driver = new WebDriverBuilder().get();
+    cachedDriver = new WebDriverBuilder().get();
   }
 
   @BeforeEach
   public void startServer() {
     server = createAppServer();
     server.start();
+    driver = requireNonNull(cachedDriver, "Driver is not initialized");
   }
 
   protected abstract AppServer createAppServer();
@@ -68,9 +71,9 @@ public void stopServer() {
 
   @AfterAll
   public static void quitDriver() {
-    if (driver != null) {
-      driver.quit();
-      driver = null;
+    if (cachedDriver != null) {
+      cachedDriver.quit();
+      cachedDriver = null;
     }
   }