[java]: fix return type and docstring for getDownloadableFiles (SeleniumHQ#15293)

Author: navin772

java/src/org/openqa/selenium/remote/RemoteWebDriver.java

@@ -651,9 +651,9 @@ public void removeVirtualAuthenticator(VirtualAuthenticator authenticator) {
   }
 
   /**
-   * Retrieves the downloadable files as a map of file names and their corresponding URLs.
+   * Retrieves the names of the downloadable files.
    *
-   * @return A map containing file names as keys and URLs as values.
+   * @return A list containing the names of the downloadable files.
    * @throws WebDriverException if capability to enable downloads is not set
    */
   @Override

java/test/org/openqa/selenium/remote/RemoteWebDriverUnitTest.java

@@ -807,4 +807,21 @@ void noArgConstructorEmptyCapabilitiesTest() {
     RemoteWebDriver driver = new RemoteWebDriver() {}; // anonymous subclass
     assertThat(driver.getCapabilities()).isEqualTo(new ImmutableCapabilities());
   }
+
+  @Test
+  void getDownloadableFilesReturnsType() {
+    List<String> expectedFiles = Arrays.asList("file1.txt", "file2.pdf");
+
+    WebDriverFixture fixture =
+        new WebDriverFixture(
+            new ImmutableCapabilities("se:downloadsEnabled", true),
+            echoCapabilities,
+            valueResponder(ImmutableMap.of("names", expectedFiles)));
+
+    List<String> result = fixture.driver.getDownloadableFiles();
+
+    assertThat(result).isInstanceOf(List.class).isEqualTo(expectedFiles);
+
+    fixture.verifyCommands(new CommandPayload(DriverCommand.GET_DOWNLOADABLE_FILES, emptyMap()));
+  }
 }