--edgeCount;
    }
    if (isDirected()) { // In undirected graphs, the successor and predecessor sets are equal.
      // Since views are returned, we need to copy the predecessors that will be removed.
      // Thus we avoid modifying the underlying view while iterating over it.
      for (N predecessor : ImmutableList.copyOf(connections.predecessors())) {
        // requireNonNull is safe because the node is a predecessor.

  /**
   * Path of extension directory or directories.
   *
   * @deprecated This property was <a
   *     href="https://openjdk.java.net/jeps/220#Removed:-The-extension-mechanism">deprecated</a> in
   *     Java 8 and removed in Java 9. We do not plan to remove this API from Guava, but if you are
   *     using it, it is probably not doing what you want.
   */
  @Deprecated
  JAVA_EXT_DIRS("java.ext.dirs"),

  /**
   * Path of extension directory or directories.
   *
   * @deprecated This property was <a
   *     href="https://openjdk.java.net/jeps/220#Removed:-The-extension-mechanism">deprecated</a> in
   *     Java 8 and removed in Java 9. We do not plan to remove this API from Guava, but if you are
   *     using it, it is probably not doing what you want.
   */
  @Deprecated
  JAVA_EXT_DIRS("java.ext.dirs"),

    assertEquals("B", peekingIterator.peek());

    /* Should complain on attempt to remove() after peek(). */
    try {
      peekingIterator.remove();
      fail("remove() should throw IllegalStateException after a peek()");
    } catch (IllegalStateException e) {
      /* expected */
    }

    assertEquals(
        "After remove() throws exception, peek should still be ok", "B", peekingIterator.peek());

   * this graph.
   *
   * <p>This is equal to the union of {@link #predecessors(Object)} and {@link #successors(Object)}.
   *
   * <p>If {@code node} is removed from the graph after this method is called, the {@code Set}
   * {@code view} returned by this method will be invalidated, and will throw {@code
   * IllegalStateException} if it is accessed in any way, with the following exceptions:

import static com.google.common.base.Preconditions.checkState;
import static com.google.common.graph.GraphConstants.ENDPOINTS_MISMATCH;
import static com.google.common.graph.GraphConstants.NODE_PAIR_REMOVED_FROM_GRAPH;
import static com.google.common.graph.GraphConstants.NODE_REMOVED_FROM_GRAPH;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterators;
import com.google.common.collect.Sets;

      // all of the listed keys, for some reason the "java.compiler" key returns null in some JVMs.
      if (property == JAVA_COMPILER) {
        continue;
      }
      // Removed in Java 9:
      // https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-2C896CA8-927C-4381-A737-B1D81D964B7B
      if (property == JAVA_EXT_DIRS) {
        continue;
      }

    the [Guava Beta Checker] to ensure that you do not use any `@Beta` APIs!**

2.  APIs without `@Beta` will remain binary-compatible for the indefinite
    future. (Previously, we sometimes removed such APIs after a deprecation
    period. The last release to remove non-`@Beta` APIs was Guava 21.0.) Even
    `@Deprecated` APIs will remain (again, unless they are `@Beta`). We have no
    plans to start removing things again, but officially, we're leaving our

    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertEdgeRemovedFromGraphErrorMessage(Throwable throwable) {
    assertThat(throwable).hasMessageThat().startsWith(EDGE_STRING);
    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertStronglyEquivalent(Graph<?> graphA, Graph<?> graphB) {

    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertEdgeRemovedFromGraphErrorMessage(Throwable throwable) {
    assertThat(throwable).hasMessageThat().startsWith(EDGE_STRING);
    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_REMOVED);
  }

  static void assertStronglyEquivalent(Graph<?> graphA, Graph<?> graphB) {