* Fully maps a file read-only in to memory as per {@link
   * FileChannel#map(java.nio.channels.FileChannel.MapMode, long, long)}.
   *
   * <p>Files are mapped from offset 0 to its length.
   *
   * <p>This only works for files ≤ {@link Integer#MAX_VALUE} bytes.
   *
   * @param file the file to map
   * @return a read-only buffer reflecting {@code file}
   * @throws FileNotFoundException if the {@code file} does not exist

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tester to ensure forwarding wrapper works by delegating calls to the corresponding method with
 * the same parameters forwarded and return value forwarded back or exception propagated as is.
 *
 * <p>For example:
 *
 * {@snippet :

#### Http2Stream

This lock guards the internal state of each stream. As above, it is never held for blocking operations. When we need to hold an application thread to block a read, we use wait/notify on this lock. This works because the lock is released while `wait()` is waiting.

#### Http2Writer

 * hint, so this technique may fail at the whim of the JDK implementation, for example if a user
 * specified the JVM flag {@code -XX:+DisableExplicitGC}. But in practice, it works very well for
 * ordinary tests.
 *
 * <p>Failure of the expected event to occur within an implementation-defined "reasonable" time
 * period or an interrupt while waiting for the expected event will result in a {@link

    Response originalResponse = chain.proceed(chain.request());
    return originalResponse.newBuilder()
        .header("Cache-Control", "max-age=60")
        .build();
  }
};
```

    .heldCertificate(localhostCertificate)
    .build();
MockWebServer server = new MockWebServer();
server.useHttps(serverCertificates.sslSocketFactory(), false);
```

`HandshakeCertificates` also works for clients where its job is to define which root certificates
to trust. In this simplified example we trust the server's self-signed certificate:

```java

      byte[] got = out.toByteArray();
      for (int i = 0; i < expected.length; i++) {
        assertEquals(expected[i], got[i]);
      }
    }
  }

  // Assumes that AbstractNonStreamingHashFunction works properly (must be tested elsewhere!)
  private static class Control extends AbstractNonStreamingHashFunction {
    @Override
    public HashCode hashBytes(byte[] input, int off, int len) {

    return response.body().string();
  }
}
```

Further examples are on the [OkHttp Recipes page][recipes].


Requirements
------------

OkHttp works on Android 5.0+ (API level 21+) and Java 8+.

On Android, OkHttp uses [AndroidX Startup][androidx_startup]. If you disable the initializer in the manifest,

    // It would be nice to be able to return a real concurrent
    // collection like ConcurrentLinkedQueue, so that e.g. concurrent
    // iteration would work, but that would not be GWT-compatible.
    // We are not "just" inheriting from ArrayList here as this doesn't work for J2kt.
    return new AbstractList<T>() {
      final ArrayList<T> data = new ArrayList<>();

      @Override
      public int size() {

            fail("scroll method should exist with correct signature");
        }
    }

    public void test_XContentBuilderCallback_interface() {
        // Test that the functional interface works correctly
        XContentBuilderCallback callback = (builder, params) -> {
            builder.startObject();
            builder.field("callback", "test");
            builder.endObject();
            return builder;