}

    ImmutableMap<Integer, Integer> map = RegularImmutableMap.fromEntries(entries);
    Set<Integer> keySet = map.keySet();
    Collection<Integer> values = map.values();

    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bytes);
    oos.writeObject(map);
    oos.flush();

    int mapSize = bytes.size();
    oos.writeObject(keySet);

    ImmutableMap<Integer, Integer> map = RegularImmutableMap.create(entries.length / 2, entries);
    Set<Integer> keySet = map.keySet();
    Collection<Integer> values = map.values();

    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bytes);
    oos.writeObject(map);
    oos.flush();

    int mapSize = bytes.size();
    oos.writeObject(keySet);

    } catch (InterruptedException ie) {
      threadUnexpectedException(ie);
    }
  }

  @SuppressWarnings("unchecked")
  <T> T serialClone(T o) {
    try {
      ByteArrayOutputStream bos = new ByteArrayOutputStream();
      ObjectOutputStream oos = new ObjectOutputStream(bos);
      oos.writeObject(o);
      oos.flush();
      oos.close();

  @J2ktIncompatible
  @GwtIncompatible // java serialization not supported in GWT.
  private static byte[] serializeWithBackReference(Object original, int handleOffset)
      throws IOException {
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream out = new ObjectOutputStream(bos);

    out.writeObject(original);

    byte[] handle = toByteArray(baseWireHandle + handleOffset);

    } catch (InterruptedException ie) {
      threadUnexpectedException(ie);
    }
  }

  @SuppressWarnings("unchecked")
  <T> T serialClone(T o) {
    try {
      ByteArrayOutputStream bos = new ByteArrayOutputStream();
      ObjectOutputStream oos = new ObjectOutputStream(bos);
      oos.writeObject(o);
      oos.flush();
      oos.close();

  @J2ktIncompatible
  @GwtIncompatible // java serialization not supported in GWT.
  private static byte[] serializeWithBackReference(Object original, int handleOffset)
      throws IOException {
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream out = new ObjectOutputStream(bos);

    out.writeObject(original);

    byte[] handle = toByteArray(baseWireHandle + handleOffset);

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;