error out java version below 21

Author: harshyyy21

CHANGELOG.md

@@ -1 +1,2 @@
+- Removes support for running emulators with Java versions prior to 21.
 - [Added] support for new google-genai plugin during `init genkit` (#8957)

src/emulator/commandUtils.ts

@@ -589,5 +589,5 @@ export async function checkJavaMajorVersion(): Promise<number> {
 
 export const MIN_SUPPORTED_JAVA_MAJOR_VERSION = 21;
 export const JAVA_DEPRECATION_WARNING =
-  "firebase-tools will drop support for Java version < 21 soon in firebase-tools@15. " +
+  "firebase-tools no longer supports Java version before 21. " +
   "Please install a JDK at version 21 or above to get a compatible runtime.";

src/emulator/controller.ts

@@ -299,7 +299,7 @@ export async function startAll(
   if (targets.some(requiresJava)) {
     if ((await commandUtils.checkJavaMajorVersion()) < MIN_SUPPORTED_JAVA_MAJOR_VERSION) {
       utils.logLabeledError("emulators", JAVA_DEPRECATION_WARNING, "warn");
-      deprecationNotices.push(JAVA_DEPRECATION_WARNING);
+      throw new FirebaseError(JAVA_DEPRECATION_WARNING);
     }
   }
   if (options.logVerbosity) {