Elasticsearch builds using Gradle and Java 16. When importing into Eclipse you
will either need to use an appropriate JDK to run Eclipse itself (e.g. by
specifying the VM in [eclipse.ini](https://wiki.eclipse.org/Eclipse.ini) or by
defining the JDK Gradle uses by setting **Preferences** > **Gradle** >
**Advanced Options** > **Java home** to an appropriate version.

/**
 * A {@link Map} whose contents will never change, with many other important properties detailed at
 * {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use ImmutableMap.of or another implementation")
@GwtCompatible

      // BigInteger.gcd is consistent with this decision.
      return b;
    } else if (b == 0) {
      return a; // similar logic
    }
    /*
     * Uses the binary GCD algorithm; see http://en.wikipedia.org/wiki/Binary_GCD_algorithm. This is
     * >60% faster than the Euclidean algorithm in benchmarks.
     */
    int aTwos = Long.numberOfTrailingZeros(a);
    a >>= aTwos; // divide out all 2s

 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting map will
 * not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 * @since 2.0 (implements {@code NavigableMap} since 12.0)
 */
@GwtCompatible

 *   if ({@link #ascii() ascii()}.{@link #matchesAllOf matchesAllOf}(s)) { ... }</pre>
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/StringsExplained#charmatcher">{@code CharMatcher}
 * </a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible
public abstract class CharMatcher implements Predicate<Character> {
  /*

 *   if ({@link #ascii() ascii()}.{@link #matchesAllOf matchesAllOf}(s)) { ... }</pre>
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/StringsExplained#charmatcher">{@code CharMatcher}
 * </a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible
public abstract class CharMatcher implements Predicate<Character> {
  /*

 * are <i>lazy</i>, which means that they only advance the backing iteration when absolutely
 * necessary.
 *
 * <p>See the Guava User Guide section on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#iterables">{@code
 * Iterators}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public final class Iterators {
  private Iterators() {}

 * are <i>lazy</i>, which means that they only advance the backing iteration when absolutely
 * necessary.
 *
 * <p>See the Guava User Guide section on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#iterables">{@code
 * Iterators}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public final class Iterators {
  private Iterators() {}

 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting map will
 * not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 * @since 2.0 (implements {@code NavigableMap} since 12.0)
 */
@GwtCompatible

          <description>
            <![CDATA[
              The timezone the contributor is in. Typically, this is a number in the range
              <a href="http://en.wikipedia.org/wiki/UTC%E2%88%9212:00">-12</a> to <a href="http://en.wikipedia.org/wiki/UTC%2B14:00">+14</a>
              or a valid time zone id like "America/Montreal" (UTC-05:00) or "Europe/Paris" (UTC+01:00).
            ]]>
          </description>