* build tools and environments.
 *
 * <p>A toolchain represents a specific build tool configuration (e.g., JDK, compiler) that can be
 * used during the Maven build process. This service allows for retrieving, storing, and managing
 * these toolchains.</p>
 *
 * @since 4.0.0
 */
@Experimental
public interface ToolchainManager extends Service {

    /**

```

### CrawlerThread (`CrawlerThread.java`)

Worker thread for crawling.

**Flow**: Poll URL → Validate → Get client → Delay → Check last-modified → Execute → Process → Extract children → Queue children → Delay

### CrawlerClientFactory

Pattern-based client selection using `LinkedHashMap<Pattern, CrawlerClient>`.

**Standard Patterns**:
```java

/**
 * Exception thrown during SSO (Single Sign-On) processing with message code support.
 *
 * This exception is used to indicate errors that occur during SSO authentication
 * and authorization processes. It carries both a message code for internationalization
 * and localization purposes, as well as detailed error information. The message code
 * can be used by the UI layer to display appropriate error messages to users.
 */

             to quit<b>)</b>
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Started reloader process <b>[</b><font color="#34E2E2"><b>383138</b></font><b>]</b> using WatchFiles
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Started server process <b>[</b><font color="#34E2E2"><b>383153</b></font><b>]</b>

 * under the License.
 */
package org.apache.maven.artifact.resolver;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.versioning.VersionRange;

/**
 * Listens to the resolution process and handles events.
 */
@Deprecated
public interface ResolutionListener {
    String ROLE = ResolutionListener.class.getName();

    int TEST_ARTIFACT = 1;

    int PROCESS_CHILDREN = 2;

/**
 * Represents an exception that occurs during the invocation of a Maven build or command.
 * This exception is typically thrown when there are errors during the execution of a Maven
 * process, such as build failures, plugin errors, or other runtime issues.
 *
 * @since 4.0.0
 */
@Experimental
public class InvokerException extends MavenException {
    /**

    /**
     * The version number of the data configuration for optimistic locking.
     * This field is required to prevent concurrent modification conflicts
     * by ensuring the configuration hasn't been modified by another process.
     */
    @Required
    @ValidateTypeFailure
    public Integer versionNo;

    /**
     * The version number of the group for optimistic locking.
     * This field is required to prevent concurrent modification conflicts
     * by ensuring the group hasn't been modified by another process.
     */
    @Required
    @ValidateTypeFailure
    public Integer versionNo;

     * The version number of the path mapping configuration for optimistic locking.
     * This field is required to prevent concurrent modification conflicts
     * by ensuring the configuration hasn't been modified by another process.
     */
    @Required
    @ValidateTypeFailure
    public Integer versionNo;

     * The version number of the related content configuration for optimistic locking.
     * This field is required to prevent concurrent modification conflicts
     * by ensuring the configuration hasn't been modified by another process.
     */
    @Required
    @ValidateTypeFailure
    public Integer versionNo;