[java] JSpecify annotations for ExpectedCondition (#16489)

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

Author: mk868

java/src/org/openqa/selenium/support/ui/BUILD.bazel

@@ -58,5 +58,6 @@ java_library(
         "//java/src/org/openqa/selenium:core",
         "//java/src/org/openqa/selenium/remote",
         artifact("com.google.guava:guava"),
+        artifact("org.jspecify:jspecify"),
     ],
 )

java/src/org/openqa/selenium/support/ui/ExpectedCondition.java

@@ -18,6 +18,8 @@
 package org.openqa.selenium.support.ui;
 
 import com.google.common.base.Function;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.openqa.selenium.WebDriver;
 
 /**
@@ -34,5 +36,6 @@
 // NB: this originally extended Guava's Function interface since Java didn't have one. To avoid code
 // such as "com.google.common.base.Function condition = ExpectedConditions.elementFound(By);"
 // breaking at compile time, we continue to extend Guava's Function interface.
-public interface ExpectedCondition<T>
+@NullMarked
+public interface ExpectedCondition<T extends @Nullable Object>
     extends Function<WebDriver, T>, java.util.function.Function<WebDriver, T> {}