[Demonstration 1]

[Buggy Method]
@Override
public void registerListeners(@NotBlank String queue, @NotEmpty List<String> listeners) {
    final Queue queueEntity = queue(queue);
    logger.info("-- registering listeners={} to: {} --", listeners, queue);
    for (String listener : listeners) {
        listener = StringUtils.trimToEmpty(listener);
        MessageListener messageListener = messageListenerRepository.findByQueueAndUrl(queueEntity, listener);
        boolean registered = messageListener != null;
        if (!registered) {
            messageListenerRepository.save(new MessageListener().setQueue(queueEntity).setUrl(listener));
            startListener(messageListener);
        }
        logger.info("-- {} " + (registered ? "already " : "") + "registered for: {} --", listener, queue);
    }
}

[Buggy Hunk]
messageListenerRepository.save(new MessageListener().setQueue(queueEntity).setUrl(listener));

[Patch]
messageListener = messageListenerRepository.save(new MessageListener().setQueue(queueEntity).setUrl(listener));

[Demonstration 2]

[Buggy Method]
@Override
public void fillToStringProperties(Map<String, Object> props) {
    super.fillToStringProperties(props);
    this.addToStringProperties(props, "messageType", this.getMessageType());
    this.addToStringProperties(props, "encrypted", this.isEncrypted());
    this.addToStringProperties(props, "messageId", this.messageId);
    this.addToStringProperties(props, "dealtWith", this.dealtWith);
    this.addToStringProperties(props, "sentByMe", this.sentByMe);
    this.addToStringProperties(props, "forProjectId", this.forProjectId);
    this.addToStringProperties(props, "when", this.when);
    this.addToStringProperties(props, "editor", this.editor.getEmail());
}

[Buggy Hunk]
this.editor.getEmail ());

[Patch]
(this.editor != null ? this.editor.getEmail () : null));

[Demonstration 3]

[Buggy Method]
@Override
public String getLabel() {
    return BundleUtil.getString(MODULE_BUNDLE, "label." + this.getClass().getSimpleName(), getCredits().toString(), getConfiguration().getCurricularPeriod().getFullLabel());
}

[Buggy Hunk]
getConfiguration().getCurricularPeriod().getFullLabel());

[Patch]
getYearMin().toString());