#### Per-Connection Locks

Each connection has its own lock. The connections in the pool are all in a `ConcurrentLinkedQueue`. Due to data races, iterators of this queue may return removed connections. Callers must check the connection's `noNewExchanges` property before using connections from the pool.

The connection lock is never held while doing I/O (even closing a socket) to prevent contention.

if ! command -v xargs >/dev/null 2>&1
then
    die "xargs is not available"
fi

# Use "xargs" to parse quoted args.
#
# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
#
# In Bash we could simply go:
#
#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
#   set -- "${ARGS[@]}" "$@"
#
# but POSIX shell has neither arrays nor command substitution, so instead we

        assertWagon("c");

        assertWagon("string");

        assertThrows(UnsupportedProtocolException.class, () -> assertWagon("d"));
    }

    /**
     * Check that transfer listeners are properly removed after getArtifact and putArtifact
     */
    @Test
    void testWagonTransferListenerRemovedAfterGetArtifactAndPutArtifact() throws Exception {

    /** Value indicating the element should be merged */
    public static final String SELF_COMBINATION_MERGE = "merge";
    /** Value indicating the element should be removed */
    public static final String SELF_COMBINATION_REMOVE = "remove";
    /**
     * Default mode for combining a DOM node during merge.
     * When element names match, the process will try to merge element attributes

            }
        }
    ]
}
```

### 3.3 Automatic removal of delete markers with no other versions

When an object has only one version as a delete marker, the latter can be automatically removed after a certain number of days using the following configuration:

```
{
    "Rules": [
        {
            "ID": "Removing all delete markers",
            "Expiration": {

arcfour256
arcfour128
arcfour
aes128-cbc
3des-cbc
```

`--sftp=mac-algos=...` specifies a default set of MAC algorithms in preference order.
This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed because they have 
reached the end of their useful life.

Valid values: 

```
******@****.***
******@****.***
hmac-sha2-256
hmac-sha2-512
hmac-sha1
hmac-sha1-96

## Version 3.13.1

_2019-02-05_

 *  Fix: Don't crash when using a custom `X509TrustManager` or `SSLSocket` on Android. When we
    removed obsolete code for Android 4.4 we inadvertently also removed support for custom
    subclasses. We've restored that support!


## Version 3.13.0

_2019-02-04_

   * class, we use a suboptimal int[] representation to avoid introducing a new type that can impede
   * class-unloading when ThreadLocals are not removed.
   */
  static final ThreadLocal<int @Nullable []> threadHashCode = new ThreadLocal<>();

  /** Generator of new random hash codes */
  static final Random rng = new Random();

  public boolean hasParent() {
    return parts.size() > 1;
  }

  /**
   * Returns an {@code InternetDomainName} that is the immediate ancestor of this one; that is, the
   * current domain with the leftmost part removed. For example, the parent of {@code
   * www.google.com} is {@code google.com}.
   *
   * @throws IllegalStateException if the domain has no parent, as determined by {@link #hasParent}
   */

   *
   * <ul>
   *   <li>You want to assign the same fraction of inputs to each bucket.
   *   <li>When you reduce the number of buckets, you can accept that the most recently added
   *       buckets will be removed first. More concretely, if you are dividing traffic among tasks,
   *       you can decrease the number of tasks from 15 and 10, killing off the final 5 tasks, and