import java.util.concurrent.Executor;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Implementations of {@code Futures.catching*}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings("nullness") // TODO(b/147136275): Remove once our checker understands & and |.
abstract class AbstractCatchingFuture<

import java.util.concurrent.Executor;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Implementations of {@code Futures.transform*}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings("nullness") // TODO(b/147136275): Remove once our checker understands & and |.
abstract class AbstractTransformFuture<

    public T get() {
      // A 2-field variant of Double Checked Locking.
      if (!initialized) {
        synchronized (this) {
          if (!initialized) {
            T t = delegate.get();
            value = t;
            initialized = true;
            return t;
          }
        }
      }
      // This is safe because we checked `initialized`.
      return uncheckedCastNullableTToT(value);
    }

  CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
  int num_devices = TF_DeviceListCount(devices);
  for (int d = 0; d < num_devices; ++d) {
    const char* name = TF_DeviceListName(devices, d, status);
    CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
    TFE_TensorHandle* copy = TFE_TensorHandleCopyToDevice(m, ctx, name, status);
    CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);

			// Blank identifiers don't get declared, so naive type-checking of the
			// receiver type expression would fail in Checker.collectParams below,
			// when Checker.ident cannot resolve the _ to a type.
			//
			// Checker.recvTParamMap maps these blank identifiers to their type parameter
			// types, so that they may be resolved in Checker.ident when they fail
			// lookup in the scope.
			for i, p := range rparams {
				if p.Value == "_" {

import java.util.concurrent.Executor;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Implementations of {@code Futures.catching*}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings("nullness") // TODO(b/147136275): Remove once our checker understands & and |.
abstract class AbstractCatchingFuture<

    public T get() {
      // A 2-field variant of Double Checked Locking.
      if (!initialized) {
        synchronized (this) {
          if (!initialized) {
            T t = delegate.get();
            value = t;
            initialized = true;
            return t;
          }
        }
      }
      // This is safe because we checked `initialized`.
      return uncheckedCastNullableTToT(value);
    }

			// Blank identifiers don't get declared, so naive type-checking of the
			// receiver type expression would fail in Checker.collectParams below,
			// when Checker.ident cannot resolve the _ to a type.
			//
			// Checker.recvTParamMap maps these blank identifiers to their type parameter
			// types, so that they may be resolved in Checker.ident when they fail
			// lookup in the scope.
			for i, p := range rparams {
				if p.Name == "_" {

    this.keyTypeOrObjectUnderJ2cl = keyType;
  }

  // Overriding these 3 methods to show that values may be null (but not keys)

  @Override
  K checkKey(K key) {
    return checkNotNull(key);
  }

  @CanIgnoreReturnValue
  @Override
  @SuppressWarnings("RedundantOverride") // b/192446478: RedundantOverride ignores some annotations.

// contexts to canonicalize instances, and it would probably be possible to
// achieve such a guarantee.

// A Context is an opaque type checking context. It may be used to share
// identical type instances across type-checked packages or calls to
// Instantiate. Contexts are safe for concurrent use.
//
// The use of a shared context does not guarantee that identical instances are
// deduplicated in all cases.
type Context struct {