core/src/main/java/io/fabric8/maven/core/service/ApplyService.java
protected String getNamespace(HasMetadata entity) {
        String answer = KubernetesHelper.getNamespace(entity);
        if (StringUtils.isBlank(answer)) {
            answer = getNamespace();
        }
        // lest make sure the namespace exists
        applyNamespace(answer);
        return answer;
    }
protected String getNamespace(HasMetadata entity) {
        String answer = KubernetesHelper.getNamespace(entity);
        if (StringUtils.isBlank(answer)) {
            answer = getNamespace();
        }
        // lest make sure the namespace exists
        applyNamespace(answer);
        return answer;
    }
Returns the namespace defined in the entity or the configured namespace