return new Joiner(separator);
  }

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(char separator) {
    return new Joiner(String.valueOf(separator));
  }

  private final String separator;

  private Joiner(String separator) {
    this.separator = checkNotNull(separator);
  }

  private Joiner(Joiner prototype) {

    return new Joiner(separator);
  }

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(char separator) {
    return new Joiner(String.valueOf(separator));
  }

  private final String separator;

  private Joiner(String separator) {
    this.separator = checkNotNull(separator);
  }

  private Joiner(Joiner prototype) {

  }

  private static void checkNoOutput(Joiner joiner, Iterable<Integer> set) {
    assertEquals("", joiner.join(set));
    assertEquals("", joiner.join(set.iterator()));

    Object[] array = Lists.newArrayList(set).toArray(new Integer[0]);
    assertEquals("", joiner.join(array));

    StringBuilder sb1FromIterable = new StringBuilder();
    assertSame(sb1FromIterable, joiner.appendTo(sb1FromIterable, set));

  }

  private static void checkNoOutput(Joiner joiner, Iterable<Integer> set) {
    assertEquals("", joiner.join(set));
    assertEquals("", joiner.join(set.iterator()));

    Object[] array = Lists.newArrayList(set).toArray(new Integer[0]);
    assertEquals("", joiner.join(array));

    StringBuilder sb1FromIterable = new StringBuilder();
    assertSame(sb1FromIterable, joiner.appendTo(sb1FromIterable, set));

   0080-009F; [CONTROL CHARACTERS]
   06DD; ARABIC END OF AYAH
   070F; SYRIAC ABBREVIATION MARK
   180E; MONGOLIAN VOWEL SEPARATOR
   200C; ZERO WIDTH NON-JOINER
   200D; ZERO WIDTH JOINER
   2028; LINE SEPARATOR
   2029; PARAGRAPH SEPARATOR
   2060; WORD JOINER
   2061; FUNCTION APPLICATION
   2062; INVISIBLE TIMES
   2063; INVISIBLE SEPARATOR
   206A-206F; [CONTROL CHARACTERS]
   FEFF; ZERO WIDTH NO-BREAK SPACE

        builder.add(field);
      }
    }
    return builder.build();
  }

  private static final Splitter SPLITTER = Splitter.on('_');
  private static final Joiner JOINER = Joiner.on('-');

  private static String upperToHttpHeaderName(
      String constantName,
      ImmutableBiMap<String, String> specialCases,
      ImmutableSet<String> uppercaseAcronyms) {

        TimeUnit unit,
        Class<?> cls,
        Joiner joiner,
        Pattern pattern,
        UnsignedInteger ui,
        UnsignedLong ul,
        StringBuilder sb,
        Predicate<?> pred,
        Function<?, ?> func,
        Object obj) {
      delegate.foo(
          s, r, n, it, b, eq, e, in, c, ord, charset, unit, cls, joiner, pattern, ui, ul, sb, pred,
          func, obj);
    }

        TimeUnit unit,
        Class<?> cls,
        Joiner joiner,
        Pattern pattern,
        UnsignedInteger ui,
        UnsignedLong ul,
        StringBuilder sb,
        Predicate<?> pred,
        Function<?, ?> func,
        Object obj) {
      delegate.foo(
          s, r, n, it, b, eq, e, in, c, ord, charset, unit, cls, joiner, pattern, ui, ul, sb, pred,
          func, obj);
    }

import static java.lang.reflect.Modifier.isPublic;
import static java.lang.reflect.Modifier.isStatic;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Objects;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;

import static java.lang.reflect.Modifier.isPublic;
import static java.lang.reflect.Modifier.isStatic;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Objects;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;