core/src/main/java/io/fabric8/maven/core/util/kubernetes/KubernetesHelper.java
public static String validateKubernetesId(String currentValue, String description) throws IllegalArgumentException {
        if (StringUtils.isBlank(currentValue)) {
            throw new IllegalArgumentException("No " + description + " is specified!");
        }
        int size = currentValue.length();
        for (int i = 0; i < size; i++) {
            char ch = currentValue.charAt(i);
            if (Character.isUpperCase(ch)) {
                throw new IllegalArgumentException("Invalid upper case letter '" + ch + "' at index " + i + " for " + description + " value: " + currentValue);
            }
        }
        return currentValue;
    }
public static String validateKubernetesId(String currentValue, String description) throws IllegalArgumentException {
        if (StringUtils.isBlank(currentValue)) {
            throw new IllegalArgumentException("No " + description + " is specified!");
        }
        int size = currentValue.length();
        for (int i = 0; i < size; i++) {
            char ch = currentValue.charAt(i);
            if (Character.isUpperCase(ch)) {
                throw new IllegalArgumentException("Invalid upper case letter '" + ch + "' at index " + i + " for " + description + " value: " + currentValue);
            }
        }
        return currentValue;
    }
Validates that the given value is valid according to the kubernetes ID parsing rules, throwing an exception if not.