Concurrency
===========

This document describes the concurrency considerations for http/2 connections and the connection pool within OkHttp.

## HTTP/2 Connections

The HttpURLConnection API is a blocking API. You make a blocking write to send a request, and a blocking read to receive the response.

#### Blocking APIs

Committer's Guides
------------------

 * [Concurrency][concurrency]
 * [Debug Logging][debug_logging]
 * [Releasing][releasing]

 [cla]: https://spreadsheets.google.com/spreadsheet/viewform?formkey=dDViT2xzUHAwRkI3X3k5Z0lQM091OGc6MQ&ndplr=1
 [concurrency]: https://square.github.io/okhttp/concurrency/
 [debug_logging]: https://square.github.io/okhttp/debug_logging/

Committer's Guides
------------------

 * [Concurrency][concurrency]
 * [Debug Logging][debug_logging]
 * [Releasing][releasing]

 [cla]: https://spreadsheets.google.com/spreadsheet/viewform?formkey=dDViT2xzUHAwRkI3X3k5Z0lQM091OGc6MQ&ndplr=1
 [concurrency]: https://square.github.io/okhttp/concurrency/
 [debug_logging]: https://square.github.io/okhttp/debug_logging/

        # Redirect all contributing pages to contribute/*
        'contributing.md': 'contribute/contributing.md'
        'code_of_conduct.md': 'contribute/code_of_conduct.md'
        'concurrency.md': 'contribute/concurrency.md'
        'debug_logging.md': 'contribute/debug_logging.md'

nav:
  - 'Overview':
    - 'Overview': index.md
    - 'Stack Overflow': https://stackoverflow.com/questions/tagged/okhttp?sort=active

    FakeTicker ticker = new FakeTicker();
    assertThrows(
        IllegalArgumentException.class, () -> ticker.setAutoIncrementStep(-1, NANOSECONDS));
  }

  @GwtIncompatible // concurrency

  public void testConcurrentAdvance() throws Exception {
    FakeTicker ticker = new FakeTicker();

    int numberOfThreads = 64;
    runConcurrentTest(
        numberOfThreads,

    public String updatedBy;

    /**
     * The timestamp when this duplicate host configuration was last updated.
     * Stored as a long value representing milliseconds since epoch.
     * Used for audit trail and concurrency control.
     */
    @ValidateTypeFailure
    public Long updatedTime;

    /**
     * The version number of the duplicate host configuration for optimistic locking.

    FakeTicker ticker = new FakeTicker();
    assertThrows(
        IllegalArgumentException.class, () -> ticker.setAutoIncrementStep(-1, NANOSECONDS));
  }

  @GwtIncompatible // concurrency

  public void testConcurrentAdvance() throws Exception {
    FakeTicker ticker = new FakeTicker();

    int numberOfThreads = 64;
    runConcurrentTest(
        numberOfThreads,

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

/**
 * {@linkplain EventBus Discouraged} in favor of dependency injection and concurrency frameworks,
 * EventBus allows publish-subscribe-style communication.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/EventBusExplained">{@code EventBus}</a>.
 */

    }
    this.initialCapacity = initialCapacity;
    return this;
  }

  @CanIgnoreReturnValue
  public MapMaker concurrencyLevel(int concurrencyLevel) {
    checkArgument(
        concurrencyLevel >= 1, "concurrency level (%s) must be at least 1", concurrencyLevel);
    // GWT technically only supports concurrencyLevel == 1, but we silently
    // ignore other positive values.
    return this;
  }

    public String updatedBy;

    /**
     * The timestamp when this elevate word configuration was last updated.
     * Stored as a long value representing milliseconds since epoch.
     * Used for audit trail and concurrency control.
     */
    @ValidateTypeFailure
    public Long updatedTime;

    /**
     * The version number of the elevate word configuration for optimistic locking.