public static boolean equal(File file1, File file2) throws IOException {
    checkNotNull(file1);
    checkNotNull(file2);
    if (file1 == file2 || file1.equals(file2)) {
      return true;
    }

    /*
     * Some operating systems may return zero as the length for files denoting system-dependent
     * entities such as devices or pipes, in which case we must fall back on comparing the bytes
     * directly.
     */

import static java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE;
import static java.nio.file.attribute.PosixFilePermission.OWNER_READ;
import static java.nio.file.attribute.PosixFilePermission.OWNER_WRITE;
import static org.junit.Assert.assertThrows;

import java.io.File;
import java.io.IOException;
import java.nio.file.attribute.PosixFileAttributeView;
import java.nio.file.attribute.PosixFileAttributes;

     has good test coverage, so look at some existing tests if you're unsure
     how to go about it.
  2. All contributions must be licensed Apache 2.0 and all files must have a
     copy of the boilerplate license comment (can be copied from an existing
     file).
  3. Files should be formatted according to Google's [Java style guide][].
  4. Please squash all commits for a change into a single commit (this can be

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Preconditions;
import java.io.File;
import java.io.FilenameFilter;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
 * File name filter that only accepts files matching a regular expression. This class is thread-safe
 * and immutable.
 *
 * @author Apple Chow
 * @since 1.0
 */

    Files.createParentDirs(file);
  }

  public void testCreateParentDirs_relativePath() throws IOException {
    File file = file("nonexistent.file");
    assertNull(file.getParentFile());
    assertNotNull(file.getCanonicalFile().getParentFile());
    Files.createParentDirs(file);
  }

  public void testCreateParentDirs_noParentsNeeded() throws IOException {
    File file = file(getTempDir(), "nonexistent.file");

 *       a more precisely named annotation?
 *   <li>While a dependency on Android ought to be easy if it's for annotations only, it will
 *       probably require adding the dep to various ACLs, license files, and Proguard
 *       configurations, and there's always the potential that something will go wrong. It
 *       <i>probably</i> won't, since the deps are needed only in tests (and maybe someday in
 *       testlib), but why bother?

      assertTrue(file.exists());
      assertThat(file.getName()).contains("FileBackedOutputStream");
      if (!isAndroid() && !isWindows()) {
        PosixFileAttributes attributes =
            java.nio.file.Files.getFileAttributeView(file.toPath(), PosixFileAttributeView.class)
                .readAttributes();
        assertThat(attributes.permissions()).containsExactly(OWNER_READ, OWNER_WRITE);
      }
    }
    out.close();

import static java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE;
import static java.nio.file.attribute.PosixFilePermission.OWNER_READ;
import static java.nio.file.attribute.PosixFilePermission.OWNER_WRITE;
import static org.junit.Assert.assertThrows;

import java.io.File;
import java.io.IOException;
import java.nio.file.attribute.PosixFileAttributeView;
import java.nio.file.attribute.PosixFileAttributes;

            <goals>
              <goal>attach-artifact</goal>
            </goals>
            <configuration>
              <artifacts>
                <artifact>
                  <file>target/publish/module.json</file>
                  <type>module</type>
                </artifact>
              </artifacts>
            </configuration>
          </execution>
        </executions>
      </plugin>

        // Permissions needed by the junit test harness
        new RuntimePermission("accessDeclaredMembers"),
        new PropertyPermission("*", "read"),
        new java.io.FilePermission("<<ALL FILES>>", "read"));
  }

  /** Sleeps until the given time has elapsed. Throws AssertionFailedError if interrupted. */
  void sleep(long millis) {
    try {
      delay(millis);
    } catch (InterruptedException ie) {