builder.append(buf, 0, read);
    }
    assertThat(builder.toString()).isEqualTo(expected);
    assertFullyRead(reader);

    // read all to one CharBuffer
    reader = new CharSequenceReader(charSequence);
    CharBuffer buf2 = CharBuffer.allocate(expected.length());
    assertEquals(expected.isEmpty() ? -1 : expected.length(), reader.read(buf2));
    Java8Compatibility.flip(buf2);

      builder.append(buf, 0, read);
    }
    assertThat(builder.toString()).isEqualTo(expected);
    assertFullyRead(reader);

    // read all to one CharBuffer
    reader = new CharSequenceReader(charSequence);
    CharBuffer buf2 = CharBuffer.allocate(expected.length());
    assertEquals(expected.isEmpty() ? -1 : expected.length(), reader.read(buf2));
    Java8Compatibility.flip(buf2);

@J2ktIncompatible
@GwtIncompatible
public final class CharStreams {

  // 2K chars (4K bytes)
  private static final int DEFAULT_BUF_SIZE = 0x800;

  /** Creates a new {@code CharBuffer} for buffering reads or writes. */
  static CharBuffer createBuffer() {
    return CharBuffer.allocate(DEFAULT_BUF_SIZE);
  }

  private CharStreams() {}

  /**
   * Copies all characters between the {@link Readable} and {@link Appendable} objects. Does not

  }

  @J2ktIncompatible // J2kt CharBuffer does not implement CharSequence so not recognized as empty
  @GwtIncompatible // CharBuffer not available
  public void testToStringOmitEmptyValues_charBuffer() {
    String toTest =
        MoreObjects.toStringHelper(new TestClass())
            .omitEmptyValues()
            .add("field1", "Hello")
            .add("field2", CharBuffer.allocate(0))
            .toString();

import com.google.common.collect.Lists;
import java.io.BufferedReader;
import java.io.FilterReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.jspecify.annotations.NullUnmarked;

/**
 * Unit tests for {@link LineBuffer} and {@link LineReader}.
 *

      File file = getFile();
      Reader reader = new InputStreamReader(new FileInputStream(file), UTF_8);
      StringBuilder builder = new StringBuilder();
      CharBuffer buffer = CharBuffer.allocate(100);
      while (reader.read(buffer) != -1) {
        Java8Compatibility.flip(buffer);
        builder.append(buffer);
        Java8Compatibility.clear(buffer);
      }

  Readable generateReadable() {
    return generateReader();
  }

  @Generates
  Buffer generateBuffer() {
    return generateCharBuffer();
  }

  @Generates
  CharBuffer generateCharBuffer() {
    return CharBuffer.allocate(generateInt());
  }

  @Generates
  ByteBuffer generateByteBuffer() {
    return ByteBuffer.allocate(generateInt());
  }

  @Generates

  Readable generateReadable() {
    return generateReader();
  }

  @Generates
  Buffer generateBuffer() {
    return generateCharBuffer();
  }

  @Generates
  CharBuffer generateCharBuffer() {
    return CharBuffer.allocate(generateInt());
  }

  @Generates
  ByteBuffer generateByteBuffer() {
    return ByteBuffer.allocate(generateInt());
  }

  @Generates

          .put(Reader.class, new StringReader(""))
          .put(StringReader.class, new StringReader(""))
          .put(Buffer.class, ByteBuffer.allocate(0))
          .put(CharBuffer.class, CharBuffer.allocate(0))
          .put(ByteBuffer.class, ByteBuffer.allocate(0))
          .put(ShortBuffer.class, ShortBuffer.allocate(0))
          .put(IntBuffer.class, IntBuffer.allocate(0))

    assertEquals(-1, ArbitraryInstances.get(Readable.class).read(CharBuffer.allocate(1)));
    assertEquals(-1, ArbitraryInstances.get(Reader.class).read());
    assertEquals(-1, ArbitraryInstances.get(StringReader.class).read());
    assertEquals(0, ArbitraryInstances.get(Buffer.class).capacity());
    assertEquals(0, ArbitraryInstances.get(CharBuffer.class).capacity());