return Platform.stringIsNullOrEmpty(string);
  }

  /**
   * Returns a string, of length at least {@code minLength}, consisting of {@code string} prepended
   * with as many copies of {@code padChar} as are necessary to reach that length. For example,
   *
   * <ul>
   *   <li>{@code padStart("7", 3, '0')} returns {@code "007"}
   *   <li>{@code padStart("2010", 3, '0')} returns {@code "2010"}

import java.util.SortedSet;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link Set} whose contents will never change, with many other important properties detailed at
 * {@link ImmutableCollection}.
 *
 * @since 2.0
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization

 *
 * <p>{@code Iterator} requires its implementations to support querying the end-of-data status
 * without changing the iterator's state, using the {@link #hasNext} method. But many data sources,
 * such as {@link java.io.Reader#read()}, do not expose this information; the only way to discover
 * whether there is any data left is by trying to retrieve it. These types of data sources are

      return count(element);
    }
    int index = element.ordinal();
    int oldCount = counts[index];
    long newCount = (long) oldCount + occurrences;
    checkArgument(newCount <= Integer.MAX_VALUE, "too many occurrences: %s", newCount);
    counts[index] = (int) newCount;
    if (oldCount == 0) {
      distinctElements++;
    }
    size += occurrences;
    return oldCount;
  }

  // Modification Operations

    expected.addAll(index, elements);
    expectContents(expected);
  }

  /*
   * TODO: if we're testing a list, we could check indexOf(). (Doing it in
   * AbstractListTester isn't enough because many tests that run on lists don't
   * extends AbstractListTester.) We could also iterate over all elements to
   * verify absence
   */
  protected void expectMissing(E... elements) {
    for (E element : elements) {

   * only the entries for {@code keys} will be returned from {@code getAll}.
   *
   * <p>This method should be overridden when bulk retrieval is significantly more efficient than
   * many individual lookups. Note that {@link LoadingCache#getAll} will defer to individual calls
   * to {@link LoadingCache#get} if this method is not overridden.
   *

import java.util.Iterator;
import java.util.List;
import java.util.stream.Collector;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Provides static methods for working with {@link Comparator} instances. For many other helpful
 * comparator utilities, see either {@code Comparator} itself (for Java 8+), or {@code
 * com.google.common.collect.Ordering} (otherwise).
 *
 * <h3>Relationship to {@code Ordering}</h3>
 *

                }
                descriptors = Collections.singletonMap(file, name);
                isModuleHierarchy = false;
                return;
            }
            /*
             * Module hierarchy: many modules, one per directory, with descriptor at the root of the sub-directory.
             * This is the layout of output directories in projects using the new (Java 9 and later) way to organize
             * source files.

   * without contention. Because assignment of entries to these partitions is not necessarily
   * uniform, the actual concurrency observed may vary. Ideally, you should choose a value to
   * accommodate as many threads as will ever concurrently modify the table. Using a significantly
   * higher value than you need can waste space and time, and a significantly lower value can lead

   * that satisfy the filter will be removed from the underlying set.
   *
   * <p>The returned set isn't threadsafe or serializable, even if {@code unfiltered} is.
   *
   * <p>Many of the filtered set's methods, such as {@code size()}, iterate across every element in
   * the underlying set and determine which elements satisfy the filter. When a live view is