```

////

These dependencies will be executed/solved the same way as normal dependencies. But their value (if they return any) won't be passed to your *path operation function*.

/// tip

Some editors check for unused function parameters, and show them as errors.

Using these `dependencies` in the *path operation decorator* you can make sure they are executed while avoiding editor/tooling errors.

    boolean executed = false;

    public void add(Runnable runnable, Executor executor) {
      Preconditions.checkNotNull(runnable, "Runnable was null.");
      Preconditions.checkNotNull(executor, "Executor was null.");

      boolean executeImmediate = false;

      synchronized (runnables) {
        if (!executed) {

You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

```Python hl_lines="1  15"
{!../../docs_src/debugging/tutorial001.py!}
```

### About `__name__ == "__main__"`

The main purpose of the `__name__ == "__main__"` is to have some code that is executed when your file is called with:

<div class="termy">

```console
$ python myapp.py
```

</div>

but is not called when another file imports it, like in:

```Python
from myapp import app
```

        }
    }

    protected static class ProcessDestroyer extends TimerTask {

        private final Process p;

        private final InputStreamThread ist;

        private final AtomicBoolean executed = new AtomicBoolean(false);

        private final long timeout;

        public ProcessDestroyer(final Process p, final InputStreamThread ist, final long timeout) {
            this.p = p;

Only the code prior to and including the `yield` statement is executed before creating a response:

```Python hl_lines="2-4"
{!../../docs_src/dependencies/tutorial007.py!}
```

The yielded value is what is injected into *path operations* and other dependencies:

```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

The code following the `yield` statement is executed after the response has been delivered:

# Apache Maven Encrypt Script
#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.
# -----------------------------------------------------------------------------

    // the underlying supplier hasn't executed yet
    assertEquals(0, countingSupplier.calls);

    assertEquals(10, (int) memoizedSupplier.get());

    // now it has
    assertEquals(1, countingSupplier.calls);

    assertEquals(10, (int) memoizedSupplier.get());

    // it still should only have executed once due to memoization
    assertEquals(1, countingSupplier.calls);
  }

    // the underlying supplier hasn't executed yet
    assertEquals(0, countingSupplier.calls);

    assertEquals(10, (int) memoizedSupplier.get());

    // now it has
    assertEquals(1, countingSupplier.calls);

    assertEquals(10, (int) memoizedSupplier.get());

    // it still should only have executed once due to memoization
    assertEquals(1, countingSupplier.calls);
  }

# Apache Maven Debug Script
#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.
#   MAVEN_DEBUG_ADDRESS (Optional) Set the debug address. Default value is localhost:8000