*/
public abstract class StringUtil {

    /**
     * Do not instantiate.
     */
    protected StringUtil() {
    }

    /**
     * A system line separator.
     */
    public static final String RETURN_STRING = System.getProperty("line.separator");

    /**
     * An empty string <code>""</code>.
     */
    public static final String EMPTY = "";

    /**
     * An empty array of strings.

                try {
                    final String line = br.readLine();
                    if (line == null) {
                        break;
                    }
                    if (logger.isDebugEnabled()) {
                        logger.debug(line);
                    }
                    list.add(line);
                    if (list.size() > maxLineBuffer) {
                        list.remove(0);

                if (!line.startsWith("#")) {
                    final String urlValue;
                    if (urlEncodeDisabled.get()) {
                        urlValue = line;
                        urlEncodeDisabled.set(false);
                    } else {
                        urlValue = systemHelper.encodeUrlFilter(line);
                    }

        if (locale == null) {
            return Locale.ROOT;
        }
        return locale;
    }

    /**
     * Formats a file size in bytes to a human-readable string with appropriate units.
     *
     * @param value the file size in bytes
     * @return formatted file size string (e.g., "1.5M", "2.3G", "512K")
     */
    public static String formatFileSize(final long value) {
        double target = value;

        if (stemmerOverrideItemList == null) {
            reload(null);
        }

        if (offset >= stemmerOverrideItemList.size() || offset < 0) {
            return new PagingList<>(Collections.<StemmerOverrideItem> emptyList(), offset, size, stemmerOverrideItemList.size());
        }

        int toIndex = offset + size;

            try {
                logger.fine(() -> ">>> " + method + " " + finalUrl);
                final URL u = new URL(finalUrl);
                connection = open(u);
                connection.setRequestMethod(method.toString());
                if (headerList != null) {
                    for (final String[] values : headerList) {
                        logger.fine(() -> ">>> " + values[0] + "=" + values[1]);

            return new PagingList<>(Collections.<CharMappingItem> emptyList(), offset, size, mappingItemList.size());
        }

        int toIndex = offset + size;
        if (toIndex > mappingItemList.size()) {
            toIndex = mappingItemList.size();
        }

        return new PagingList<>(mappingItemList.subList(offset, toIndex), offset, size, mappingItemList.size());
    }

mvn formatter:format           # Format code
mvn license:format             # Update license headers
```

### Code Style

- 4 spaces (no tabs)
- Opening brace on same line
- Max line length: 120
- JavaDoc required for public APIs
- License headers required

### Testing

**Structure**: `src/test/java/org/codelibs/fess/crawler/`
**Frameworks**: JUnit 4, UTFlute, Mockito, Testcontainers

import org.opensearch.monitor.process.ProcessProbe;

import jakarta.annotation.Resource;

/**
 * Executable class for generating thumbnails for indexed documents.
 * This class provides a command-line interface for thumbnail generation tasks.
 */
public class ThumbnailGenerator {

    private static final Logger logger = LogManager.getLogger(ThumbnailGenerator.class);

    /**

labels.wizard_start_crawler_title=Crawler
labels.wizard_start_crawling_desc=Sie können das Crawling jetzt starten, indem Sie auf die Schaltfläche "Crawling starten" klicken.
labels.wizard_button_start_crawling=Crawling starten
labels.wizard_button_finish=Überspringen
labels.search_list_configuration=Suchen
labels.search_list_button_delete=Löschen
labels.search_list_delete_confirmation=Sind Sie sicher, dass Sie löschen möchten?