└── fess-crawler-opensearch/  # OpenSearch backend
```

### Key Components

#### Core Engine
- **Crawler**: Main orchestrator managing crawl execution
- **CrawlerContext**: Execution context and configuration
- **CrawlerThread**: Individual crawler thread implementation

#### Client Architecture
- **HcHttpClient**: HTTP/HTTPS client using Apache HttpComponents

    }

    /**
     * Closes the stream and deletes the temporary file if it was not retrieved.
     * If an error occurs during file deletion, it is logged but not thrown to avoid
     * masking exceptions from the main operation.
     *
     * @throws IOException if an I/O error occurs during stream closure
     */
    @Override
    public void close() throws IOException {
        try {
            super.close();

 */
package org.codelibs.fess.exception;

/**
 * Exception thrown during SSO (Single Sign-On) processing operations.
 *
 * This exception is used to indicate errors that occur during the execution
 * of SSO authentication and authorization processes. It extends FessSystemException
 * to provide consistent error handling within the Fess system for SSO-related

    private final List<ScoreBooster> scoreBoosterList = new ArrayList<>();

    /**
     * Executes all score boosters.
     * @return The result of the execution.
     */
    public String execute() {
        final StringBuilder resultBuf = new StringBuilder();
        scoreBoosterList.forEach(b -> {
            try {
                final long count = b.process();

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

# END TF TEST SUITE OPTIONS

# START CROSS-COMPILE CONFIGS
# Set execution platform to Linux x86
# Note: Lot of the "host_" flags such as "host_cpu" and "host_crosstool_top"
# flags seem to be actually used to specify the execution platform details. It
# seems it is this way because these flags are old and predate the distinction
# between host and execution platform.
common:cross_compile_base --config=clang_local

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.execution;

import java.util.List;

import org.apache.maven.project.MavenProject;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertNotNull;

/**
 * Denotes that a bean should be created as a singleton instance.
 * <p>
 * Singleton-scoped beans are instantiated once and reused throughout the entire
 * Maven execution. This scope should be used for stateless services or components
 * that can be safely shared across the entire build process.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Singleton

- plugin artifact retrieval problem
- plugin dependency metadata missing
- plugin dependency metadata retrieval problem
- plugin configuration problem
- plugin execution failure due to something that is known to possibly go wrong (like compilation failure)
- plugin execution error due to something that is not expected to go wrong (the compiler executable missing)

          }
        };

    List<Throwable> exceptions = runThreadsAndReturnExceptions(numThreads, task);

    assertThat(exceptions).isEmpty();
  }

  private static List<Throwable> runThreadsAndReturnExceptions(int numThreads, Runnable task) {
    List<Thread> threads = new ArrayList<>(numThreads);
    List<Throwable> exceptions = new ArrayList<>(numThreads);
    for (int i = 0; i < numThreads; i++) {