Java到Kotlin转换扩展了Abstract类

Question

我正在转换一个Java类，按照下面的代码扩展了一个抽象类

public class BadRequestAlertException extends AbstractThrowableProblem {

    private static final long serialVersionUID = 1L;

    private final String entityName;

    private final String errorKey;

    public BadRequestAlertException(String defaultMessage, String entityName, String errorKey) {
        this(ErrorConstants.DEFAULT_TYPE, defaultMessage, entityName, errorKey);
    }

    public BadRequestAlertException(URI type, String defaultMessage, String entityName, String errorKey) {
        super(type, defaultMessage, Status.BAD_REQUEST, null, null, null, getAlertParameters(entityName, errorKey));
        this.entityName = entityName;
        this.errorKey = errorKey;
    }

    public String getEntityName() {
        return entityName;
    }

    public String getErrorKey() {
        return errorKey;
    }

    private static Map<String, Object> getAlertParameters(String entityName, String errorKey) {
        Map<String, Object> parameters = new HashMap<>();
        parameters.put("message", "error." + errorKey);
        parameters.put("params", entityName);
        return parameters;
    }
}

按照以下实施方式进入Kotlin

class BadRequestAlertException(type: URI = ErrorConstants.DEFAULT_TYPE, defaultMessage: String, val entityName: String, val errorKey: String) : AbstractThrowableProblem(type, defaultMessage, Status.BAD_REQUEST, null, null, null, getAlertParameters(entityName, errorKey)) {

    companion object {
        private const val serialVersionUID = 1L

        private fun getAlertParameters(entityName: String, errorKey: String): Map<String, Any> {
            val parameters = HashMap<String, Any>()
            parameters["message"] = "error.$errorKey"
            parameters["params"] = entityName
            return parameters
        }
    }
}

Kotlin实现引发以下错误Class 'BadRequestAlertException' is not abstract and does not implement abstract base class member public abstract fun getCause(): Exceptional! defined in org.zalando.problem.AbstractThrowableProblem。

为什么Java版本没有实现getClause()方法，但是Kotlin要求重写该方法？转换是否有问题，还是Kotlin扩展抽象类的方式？