@Test
    public void test_multiple_commands_configuration() throws Exception {
        // Test setting multiple commands without triggering execution
        final List<String> commands =
                Arrays.asList("command1 ${url} ${outputFile}", "command2 ${url} ${outputFile}", "command3 ${url} ${outputFile}");

        generator.setCommandList(commands);

import jakarta.annotation.PostConstruct;

/**
 * Command-based thumbnail generator that executes external commands to create thumbnails.
 * Uses external tools through command execution to generate thumbnail images from documents.
 */
public class CommandGenerator extends BaseThumbnailGenerator {
    private static final Logger logger = LogManager.getLogger(CommandGenerator.class);

    /** List of command strings to execute for thumbnail generation. */

| Search Engine | OpenSearch |
| App Server | Embedded Tomcat |
| Crawler | fess-crawler library |
| Scheduler | Lasta Job |
| Logging | Log4j2 |
| Testing | JUnit 4/5, UTFlute, REST Assured |

## Development Commands

### Setup
```bash
mvn antrun:run          # Download OpenSearch plugins (required before first build)
mvn dbflute:download    # One-time setup for DBFlute
mvn dbflute:freegen     # Generate DBFlute source code

### Download and Install/Run

Fess 15.5 is now available and can be downloaded on the [Releases page](https://github.com/codelibs/fess/releases "download"). Downloads come in 3 flavors: deb, rpm, zip.

The following commands show how to use the zip download:

    $ unzip fess-15.5.x.zip
    $ cd fess-15.5.x
    $ ./bin/fess

For more details, see the [Installation Guide](https://fess.codelibs.org/15.5/install/index.html).

### Docker

            assertNotNull(jobProcess2);
            // Since echo command completes quickly, processes might already be finished
            // So we just verify that processes were created without errors

            Set<String> sessionIds = processHelper.getRunningSessionIdSet();
            // Since echo commands complete quickly, we may not catch them running
            // Just verify no exceptions occurred

        }
    }

    private static ExecResult exec(String[] command) throws IOException, InterruptedException, ExecutionException {
        Objects.requireNonNull(command, "command");
        if (command.length == 0) {
            throw new IllegalArgumentException("command must not be empty");
        }

        ProcessBuilder pb = new ProcessBuilder(command);
        Process process = pb.start();

    protected void setUpChild() throws Exception {
        // Get the queryProcessor that was registered in parent class
        queryProcessor = ComponentUtil.getComponent("queryProcessor");

        // Register all query commands needed for testing
        new TermQueryCommand().register();
        new MatchAllQueryCommand().register();
        new PhraseQueryCommand().register();
        new BooleanQueryCommand().register();

        // Scenario 1: Command not found
        CommandExecutionException cmdNotFound = new CommandExecutionException("Command 'xyz' not found");
        assertTrue(cmdNotFound.getMessage().contains("not found"));

        // Scenario 2: Command timeout
        CommandExecutionException timeout =

                            }
                            if (Constants.CRAWLER_PROCESS_COMMAND_THREAD_DUMP.equals(command)) {
                                ThreadDumpUtil.printThreadDump();
                            } else {
                                logger.warn("Unknown process command: command={}", command);
                            }

This clearly signals to users that they are dealing with a non-public property and should expect no guarantees.

Internal properties MUST NOT be supplemented with command-line options.
They can always be passed via `-D` on the command line.

Examples of properties that follow the naming rules:

* `org.gradle.internal.operations.trace`
* `org.gradle.internal.cmdline.max.length`
* …