* that exhibits the problem.
 *
 */
public interface Problem {

    /**
     * The different severity levels for a problem, in decreasing order.
     */
    enum Severity {
        FATAL, //
        ERROR, //
        WARNING //
    }

    /**

    // optimistically fill index position with elements from lower levels,
    // moving the hole down. In most cases this reduces the number of
    // comparisons with toTrickle, but in some cases we will need to bubble it
    // all the way up again.
    int vacated = heap.fillHoleAt(index);
    // Try to see if toTrickle can be bubbled up min levels.
    int bubbledTo = heap.bubbleUpAlternatingLevels(vacated, toTrickle);

    // optimistically fill index position with elements from lower levels,
    // moving the hole down. In most cases this reduces the number of
    // comparisons with toTrickle, but in some cases we will need to bubble it
    // all the way up again.
    int vacated = heap.fillHoleAt(index);
    // Try to see if toTrickle can be bubbled up min levels.
    int bubbledTo = heap.bubbleUpAlternatingLevels(vacated, toTrickle);

import org.apache.maven.api.annotations.Nullable;
import org.apache.maven.api.cli.Logger;

/**
 * Proto {@link Logger}. Uses provided {@link PrintStream}s or {@link System} ones as fallback.
 * Supports only two levels: ERROR and WARNING, that is emitted to STDERR and STDOUT.
 */
public class ProtoLogger implements Logger {

    private final PrintWriter out;
    private final PrintWriter err;

    public ProtoLogger() {

    void setLog(Log log);

    /**
     * Furnish access to the standard Maven logging mechanism which is managed in this base class.
     *
     * @return a log4j-like logger object which allows plugins to create messages at levels of <code>"debug"</code>,
     * <code>"info"</code>, <code>"warn"</code>, and <code>"error"</code>.
     * @deprecated Use SLF4J directly
     */
    @Deprecated
    Log getLog();

 *
 * @deprecated since 4.0.0, use {@link org.apache.maven.api.services.SettingsBuilder} instead
 */
@Deprecated(since = "4.0.0")
public interface SettingsProblem {

    /**
     * The different severity levels for a problem, in decreasing order.
     */
    enum Severity {
        FATAL, //
        ERROR, //
        WARNING //
    }

    /**

 * the problem.
 *
 * @deprecated use {@link org.apache.maven.api.services.ModelBuilder} instead
 */
@Deprecated(since = "4.0.0")
public interface ModelProblem {

    /**
     * The different severity levels for a problem, in decreasing order.
     */
    enum Severity {
        FATAL, //
        ERROR, //
        WARNING //
    }

    /**
     * Version
     */
    enum Version {

## Dependency Injection

Using `BackgroundTasks` also works with the dependency injection system, you can declare a parameter of type `BackgroundTasks` at multiple levels: in a *path operation function*, in a dependency (dependable), in a sub-dependency, etc.

---

### 🎓 **Learning Resources for Gradle**

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- **[DPE University Free Courses](https://dpeuniversity.gradle.com/app/catalog)**: A collection of hands-on courses for learning Gradle, complete with project-based tasks to improve real-world skills.

    * If the token contains `foobar`, the content of the `Authorization` header would be: `Bearer foobar`.

## **FastAPI**'s `OAuth2PasswordBearer`

**FastAPI** provides several tools, at different levels of abstraction, to implement these security features.

In this example we are going to use **OAuth2**, with the **Password** flow, using a **Bearer** token. We do that using the `OAuth2PasswordBearer` class.

/// info