[java] Add nullness for net (#15083)

Co-authored-by: Diego Molina <[email protected]>

Author: mk868

java/src/org/openqa/selenium/net/DefaultNetworkInterfaceProvider.java

@@ -24,9 +24,12 @@
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.List;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.Platform;
 import org.openqa.selenium.WebDriverException;
 
+@NullMarked
 public class DefaultNetworkInterfaceProvider implements NetworkInterfaceProvider {
   // Cache the list of interfaces between instances. This is mostly used
   // to get the loopback interface, so it's ok even though interfaces may go
@@ -104,7 +107,7 @@ private String getLocalInterfaceName() {
   }
 
   @Override
-  public NetworkInterface getLoInterface() {
+  public @Nullable NetworkInterface getLoInterface() {
     final String localIF = getLocalInterfaceName();
     try {
       final java.net.NetworkInterface byName = java.net.NetworkInterface.getByName(localIF);

java/src/org/openqa/selenium/net/HostIdentifier.java

@@ -27,13 +27,16 @@
 import java.util.Enumeration;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Logger;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.Platform;
 
+@NullMarked
 public class HostIdentifier {
   private static final Logger LOG = Logger.getLogger(HostIdentifier.class.getName());
 
-  private static volatile String hostName;
-  private static volatile String hostAddress;
+  private static volatile @Nullable String hostName;
+  private static volatile @Nullable String hostAddress;
 
   private static String resolveHostName() {
     // Ideally, we'd use InetAddress.getLocalHost, but this does a reverse DNS lookup. On Windows

java/src/org/openqa/selenium/net/NetworkInterface.java

@@ -29,14 +29,17 @@
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 public class NetworkInterface {
   private static final Logger LOG = Logger.getLogger(NetworkInterface.class.getName());
 
   private final String name;
-  private java.net.NetworkInterface networkInterface;
+  private java.net.@Nullable NetworkInterface networkInterface;
   private final Iterable<InetAddress> inetAddresses;
-  private Boolean isLoopback;
+  private @Nullable Boolean isLoopback;
 
   public NetworkInterface(java.net.NetworkInterface networkInterface) {
     this(networkInterface.getName(), list(networkInterface.getInetAddresses()));
@@ -82,7 +85,7 @@ private boolean isLoopBackFromINetAddresses(Iterable<InetAddress> inetAddresses)
     return iterator.hasNext() && iterator.next().isLoopbackAddress();
   }
 
-  InetAddress getIp4LoopbackOnly() {
+  @Nullable InetAddress getIp4LoopbackOnly() {
     // Goes by the wildly unscientific assumption that if there are more than one set of
     // loopback addresses, firefox will bind to the last one we get.
     // An alternate theory if this fails is that firefox prefers 127.0.0.1
@@ -106,7 +109,7 @@ static boolean isIpv6(InetAddress address) {
     return address instanceof Inet6Address;
   }
 
-  public InetAddress getIp4NonLoopBackOnly() {
+  public @Nullable InetAddress getIp4NonLoopBackOnly() {
     for (InetAddress inetAddress : inetAddresses) {
       if (!inetAddress.isLoopbackAddress() && !isIpv6(inetAddress)) {
         return inetAddress;
@@ -115,7 +118,7 @@ public InetAddress getIp4NonLoopBackOnly() {
     return null;
   }
 
-  public InetAddress getIp6Address() {
+  public @Nullable InetAddress getIp6Address() {
     for (InetAddress inetAddress : inetAddresses) {
       if (isIpv6(inetAddress)) {
         return inetAddress;

java/src/org/openqa/selenium/net/NetworkInterfaceProvider.java

@@ -17,16 +17,20 @@
 
 package org.openqa.selenium.net;
 
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
 /**
  * Provides information about the local network interfaces.
  *
  * <p>Basically an abstraction created to allow stubbing of java.net.NetworkInterface, also soothes
  * some of the jdk1.2 idioms from this interface into jdk1.5 idioms.
  */
+@NullMarked
 public interface NetworkInterfaceProvider {
   Iterable<NetworkInterface> getNetworkInterfaces();
 
   // TODO: Remove this whole method
   // This method should only return an interface if it's named exactly "lo"
-  NetworkInterface getLoInterface();
+  @Nullable NetworkInterface getLoInterface();
 }