if _, ok := list.targets[target.ID()]; ok {
			return fmt.Errorf("target %v already exists", target.ID())
		}
		list.targets[target.ID()] = target
	}

	return nil
}

// Exists - checks whether target by target ID exists or not.
func (list *TargetList) Exists(id TargetID) bool {
	list.RLock()
	defer list.RUnlock()

	_, found := list.targets[id]
	return found
}

     * part of the public API. In particular, this method can be changed or deleted without prior notice and must not be
     * used by plugins.
     *
     * @param phase The phase to check for, must not be {@code null}.
     * @return {@code true} if the phase has been seen.
     */
    public boolean hasLifecyclePhase(String phase) {
        return lifecyclePhases.contains(phase);
    }

#### Load Balancing

     * @return new transform header instance
     */
    public static Smb2TransformHeader decode(final byte[] buffer, int bufferIndex) {
        final Smb2TransformHeader header = new Smb2TransformHeader();

        // Check protocol ID
        final int protocolId = SMBUtil.readInt4(buffer, bufferIndex);
        if (protocolId != TRANSFORM_PROTOCOL_ID) {

        ASN1ObjectIdentifier unsupported = new ASN1ObjectIdentifier("1.2.3.4.5");
        byte[] init = spnegoInitWithMechs(unsupported);

        // Host is a FQDN to pass the short-name check
        SmbUnsupportedOperationException ex =
                assertThrows(SmbUnsupportedOperationException.class, () -> auth.createContext(tc, null, "server.example.com", init, false));

<img src="/img/tutorial/security/image12.png">

## Den Benutzernamen überprüfen { #check-the-username }

Hier ist ein vollständigeres Beispiel.

Verwenden Sie eine Abhängigkeit, um zu überprüfen, ob Benutzername und Passwort korrekt sind.

    /*
     * Inputs are <every possible 10-character string of characters "a./">
     *
     * Expected outputs are generated by the code itself, but they've been
     * checked against the inputs under Bash in order to confirm that the two
     * forms are equivalent (though not necessarily minimal, though we hope this
     * to be the case). Thus, this test is more of a regression test.
     *

 * `java.net.URL` it's possible to create an awkward URL like `http:/` with scheme and path but no
 * hostname. Building APIs that consume such malformed values is difficult!
 *
 * This class has a modern API. It avoids punitive checked exceptions: [toHttpUrl] throws
 * [IllegalArgumentException] on invalid input or [toHttpUrlOrNull] returns null if the input is an
 * invalid URL. You can even be explicit about whether each component has been encoded already.
 *

* `kubeadm init` and `kubeadm join` invocations on newly installed systems can encounter a `/var/lib/kubelet is not empty` message during pre-flight checks that prevents setup. If this is the only pre-flight failure, it can be safely ignored with `--skip-preflight-checks`.

For more information, see [#53356](https://issue.k8s.io/53356#issuecomment-333748618).

        bb.put(expectedPath.getBytes(StandardCharsets.UTF_16LE));
        bb.putShort((short) 0); // null terminator

        // Decode
        referral.decode(testBuffer, 0, testBuffer.length);

        // Check
        assertEquals(3, referral.getVersion());
        assertEquals(100, referral.getSize());
        assertEquals(expectedPath, referral.getRpath());
        assertNull(referral.getAltPath());