import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.testing.features.CollectionSize;

import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static java.util.Arrays.asList;
import static java.util.Collections.singleton;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Map;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;

        String result = StringUtil.join(null, "first", "second", "third");
        assertEquals("firstnullsecondnullthird", result);
    }

    @Test
    @DisplayName("Should handle null elements in array")
    void testJoinWithNullElements() {
        String result = StringUtil.join(",", "first", null, "third");
        assertEquals("first,null,third", result);
    }

    @Test

import java.io.IOException
import java.net.SocketException
import java.security.GeneralSecurityException
import java.security.SecureRandom
import java.security.cert.X509Certificate
import java.util.Arrays
import javax.net.ssl.KeyManager
import javax.net.ssl.SSLContext
import javax.net.ssl.SSLException
import javax.net.ssl.SSLHandshakeException
import javax.net.ssl.SSLPeerUnverifiedException

        prevArray = builder.contents;
      }
    }
  }

  public void testCreation_arrayOfArray() {
    String[] array = new String[] {"a"};
    Set<String[]> set = ImmutableSet.<String[]>of(array);
    assertEquals(singleton(array), set);
  }

  @GwtIncompatible // ImmutableSet.chooseTableSize
  public void testChooseTableSize() {
    assertEquals(8, ImmutableSet.chooseTableSize(3));

    assertThat(set).containsExactly("a", "b", "c").inOrder();
  }

  public void testCreation_arrayOfArray() {
    String[] array = new String[] {"a"};
    Set<String[]> set = ImmutableSet.<String[]>of(array);
    assertEquals(singleton(array), set);
  }

  @GwtIncompatible // ImmutableSet.chooseTableSize
  public void testChooseTableSize() {
    assertEquals(8, ImmutableSet.chooseTableSize(3));

        assertThrows(SmbException.class, () -> new SID("invalid-sid"));
        assertThrows(SmbException.class, () -> new SID("S-1"));
    }

    /**
     * Test constructor with a byte array.
     */
    @Test
    void testByteArrayConstructor() {
        SID sid = new SID(adminSidBytes, 0);
        assertEquals(1, sid.revision);
        assertEquals(2, sid.sub_authority_count);

    public Object[] toArray() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toArray();
    }

    @Override
    public <T> T[] toArray(T[] array) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toArray(array);
    }

    @Override
    public void addFirst(E e) {
      assertTrue(Thread.holdsLock(mutex));
      delegate.addFirst(e);
    }

    @Override