### 3. Generate Self-contained Access Tokens

By default, a UUID is issued as an id_token in WSO2 Identity Server, which is of the first type above. But, it also can be configured to issue a self-contained id_token (JWT), which is of the second type above.

- Open the `<IS_HOME>/repository/conf/identity/identity.xml` file and uncomment the following entry under `<OAuth>` element.

```

            // this will run at most twice. The first time, the firstRun flag is turned off, and if the retry flag
            // is set on the first run, it will be turned off and not re-set on the second try. This is because the
            // only way the retry flag can be set is if ( firstRun == true ).
            while (firstRun || retry) {
                ChecksumObserver md5ChecksumObserver = null;

 *
 * <p><b>Warning:</b> {@code ArrayTable} is rarely the {@link Table} implementation you want. First,
 * it requires that the complete universe of rows and columns be specified at construction time.
 * Second, it is always backed by an array large enough to hold a value for every possible
 * combination of row and column keys. (This is rarely optimal unless the table is extremely dense.)

   * </pre>
   *
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static Throwable getRootCause(Throwable throwable) {
    // Keep a second pointer that slowly walks the causal chain. If the fast pointer ever catches
    // the slower pointer, then there's a loop.
    Throwable slowPointer = throwable;
    boolean advanceSlowPointer = false;

			r:            metadataResolutionParams{dirQuorum: 2, objQuorum: 2, strict: true},
			wantSelected: &inputSerialized[2],
			wantOk:       true,
		},
		{
			// inputSerialized[1] have older versions of the second in inputSerialized[2]
			name:         "modtimemismatch",
			m:            metaCacheEntries{inputSerialized[1], inputSerialized[1], inputSerialized[2], inputSerialized[2]},

		}
		return info, nil
	} // In all other cases cache the value upto 1sec.

	client.diskInfoCache.InitOnce(time.Second, cachevalue.Opts{},
		func(ctx context.Context) (info DiskInfo, err error) {
			ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
			defer cancel()

			nopts := DiskInfoOptions{DiskID: *client.diskID.Load(), Metrics: true}

	if err != nil {
		return err
	}
	key := eventData.S3.Bucket.Name + "/" + objectName

	data, err := json.Marshal(event.Log{EventName: eventData.EventName, Key: key, Records: []event.Event{eventData}})
	if err != nil {
		return err
	}

	headers := make(amqp091.Table)
	// Add more information here as required, but be aware to not overload headers

						}
						return
					}
					if configRetriableErrors(err) {
						decomLogIf(ctx, fmt.Errorf("Unable to resume decommission of pools %v: %w: retrying..", pools, err))
						time.Sleep(time.Second + time.Duration(r.Float64()*float64(5*time.Second)))
						continue
					}
					decomLogIf(ctx, fmt.Errorf("Unable to resume decommission of pool %v: %w", pools, err))
					return
				}
			}
		}()
	}

	return nil
}

     * simple approach would be for each caller CAS it from null to a Set populated with its
     * exception. But there's another race: If the first thread fails with an exception and a second
     * thread immediately fails with the same exception:
     *
     * Thread1: calls setException(), which returns true, context switch before it can CAS
     * seenExceptionsField to its exception
     *

  }

  @Override
  public final int size() {
    return Ints.saturatedCast(size);
  }

  /**
   * @serialData the number of distinct elements, the first element, its count, the second element,
   *     its count, and so on
   */
  @GwtIncompatible
  @J2ktIncompatible
    private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();