if (!from.renameTo(to)) {
      copy(from, to);
      if (!from.delete()) {
        if (!to.delete()) {
          throw new IOException("Unable to delete " + to);
        }
        throw new IOException("Unable to delete " + from);
      }
    }
  }

  /**
   * Reads the first line from a file. The line does not include line-termination characters, but

    RateLimiter r = RateLimiter.create(1);
    assertTrue("Unable to acquire initial permit", r.tryAcquire());
    assertFalse("Capable of acquiring secondary permit", r.tryAcquire());
  }

  public void testDoubleMinValueCanAcquireExactlyOnce() {
    RateLimiter r = RateLimiter.create(Double.MIN_VALUE, stopwatch);
    assertTrue("Unable to acquire initial permit", r.tryAcquire());

    RateLimiter r = RateLimiter.create(1);
    assertTrue("Unable to acquire initial permit", r.tryAcquire());
    assertFalse("Capable of acquiring secondary permit", r.tryAcquire());
  }

  public void testDoubleMinValueCanAcquireExactlyOnce() {
    RateLimiter r = RateLimiter.create(Double.MIN_VALUE, stopwatch);
    assertTrue("Unable to acquire initial permit", r.tryAcquire());

 * implementing new escapers. It is strongly recommended that when implementing a new escaper you
 * extend one of these classes. If you find that you are unable to achieve the desired behavior
 * using either of these classes, please contact the Java libraries team for advice.
 *
 * <p>Popular escapers are defined as constants in classes like {@link

    @SuppressWarnings("EffectivelyPrivate")
    public final void tearDown() throws IOException {
      if (!fileThreadLocal.get().delete()) {
        logger.warning("Unable to delete file: " + fileThreadLocal.get());
      }
      fileThreadLocal.remove();
    }
  }

  private static class FileByteSourceFactory extends FileFactory implements ByteSourceFactory {

    @Override

#### Merging pull requests ####

Due to Guava's nature as a subset of Google's internal codebase which is
automatically synced to the public GitHub repository, we are unable to merge
pull requests directly into the master branch. Instead, once a pull request is
ready for merging, we'll make the appropriate changes in the internal codebase

    if (!from.renameTo(to)) {
      copy(from, to);
      if (!from.delete()) {
        if (!to.delete()) {
          throw new IOException("Unable to delete " + to);
        }
        throw new IOException("Unable to delete " + from);
      }
    }
  }

  /**
   * Reads the first line from a file. The line does not include line-termination characters, but

    if (testDir != null) {
      return testDir;
    }

    URL testFileUrl = IoTestCase.class.getResource("testdata/i18n.txt");
    if (testFileUrl == null) {
      throw new RuntimeException("unable to locate testdata directory");
    }

    if (testFileUrl.getProtocol().equals("file")) {
      try {
        File testFile = new File(testFileUrl.toURI());

        validClasses.add(new WeakReference<Class<? extends Exception>>(exceptionClass));
      }
    }

    /**
     * Returns the ClassValue-using validator, or falls back to the "weak Set" implementation if
     * unable to do so.
     */
    static GetCheckedTypeValidator getBestValidator() {
      try {
        @SuppressWarnings("rawtypes") // class literals
        Class<? extends Enum> theClass =

    sslSocket: SSLSocket,
  ): ConnectPlan {
    if (connectionSpecIndex != -1) return this
    return nextConnectionSpec(connectionSpecs, sslSocket)
      ?: throw UnknownServiceException(
        "Unable to find acceptable protocols." +
          " isFallback=$isTlsFallback," +
          " modes=$connectionSpecs," +
          " supported protocols=${sslSocket.enabledProtocols!!.contentToString()}",
      )
  }