message: Update JAVA-HOWTO.md and fix missing parenthesis
diff: @@ -184,7 +184,7 @@ e.g., writing to a file:
  // and write it to a file.
  String keysetFilename = "my_keyset.json";
  CleartextKeysetHandle.write(keysetHandle, JsonKeysetWriter.withFile(
  - new File(keysetFilename));
  + new File(keysetFilename)));
  ```
  Storing cleartext keysets on disk is not recommended. Tink supports encrypting
  