This can be very useful for setting up **resources** that you need to use for the whole app, and that are **shared** among requests, and/or that you need to **clean up** afterwards. For example, a database connection pool, or loading a shared machine learning model.

## Use Case { #use-case }

Let's start with an example **use case** and then see how to solve it with this.

      return this;
    }

    public void setLoading(boolean loading) {
      this.loading = loading;
    }

    @Override
    public boolean isLoading() {
      return loading;
    }

    @Override
    public boolean isActive() {
      return !loading;
    }

    @Override
    public V waitForValue() {
      return get();
    }

      return this;
    }

    public void setLoading(boolean loading) {
      this.loading = loading;
    }

    @Override
    public boolean isLoading() {
      return loading;
    }

    @Override
    public boolean isActive() {
      return !loading;
    }

    @Override
    public V waitForValue() {
      return get();
    }

                    if (names.length < 2) {
                        continue;
                    }
                    if (logger.isDebugEnabled()) {
                        logger.debug("Loading entry: name={}", entry.getName());
                    }
                    if ("view".equals(names[0])) {
                        names[0] = themeName;

     */
    public ProtocolHelper() {
        // Default constructor
    }

    /**
     * Initializes the protocol helper by loading configured protocols from FessConfig
     * and scanning for available protocol handlers in the classpath.
     * This method is called automatically after bean construction.
     */
    @PostConstruct

        final String authorities = fessConfig.getFesenHttpSslCertificateAuthorities();
        if (StringUtil.isNotBlank(authorities)) {
            if (logger.isDebugEnabled()) {
                logger.debug("Loading certificate_authorities: path={}", authorities);
            }
            try (final InputStream in = new FileInputStream(authorities)) {

        } else if (STRATEGY_SELF_FIRST.equals(classLoadingStrategy)) {
            realm.setParentRealm(parentRealm);
        } else {
            throw new IllegalArgumentException("Unsupported class-loading strategy '"
                    + classLoadingStrategy + "'. Supported values are: " + STRATEGY_PARENT_FIRST
                    + ", " + STRATEGY_PLUGIN + " and " + STRATEGY_SELF_FIRST);
        }

    /** List of additional default fields with their boost values */
    protected List<Pair<String, Float>> additionalDefaultList = new ArrayList<>();

    /**
     * Initializes the query field configuration by loading field mappings from FessConfig.
     * This method is called after dependency injection is complete.
     * It sets up response fields, search fields, facet fields, sort fields, and other

        } else if (STRATEGY_SELF_FIRST.equals(classLoadingStrategy)) {
            realm.setParentRealm(parentRealm);
        } else {
            throw new IllegalArgumentException("Unsupported class-loading strategy '"
                    + classLoadingStrategy + "'. Supported values are: " + STRATEGY_PARENT_FIRST
                    + ", " + STRATEGY_PLUGIN + " and " + STRATEGY_SELF_FIRST);
        }

 * output stem. The file format is expected to be `input => output`.
 *
 * The class provides methods for retrieving, adding, updating, and
 * deleting stemmer override items, as well as reloading the dictionary
 * from its source file.
 */
public class StemmerOverrideFile extends DictionaryFile<StemmerOverrideItem> {
    private static final Logger logger = LogManager.getLogger(StemmerOverrideFile.class);