Java到Kotlin的转换扩展抽象类

Question

我正在根据下面的代码转换一个扩展抽象类的Java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;
}
}

按照下面的实施方式进入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版本不实现getClause()方法，而Kotlin要求重写该方法？转换有问题吗，或者只是Kotlin扩展抽象类的方式有问题吗？

Answer 1

FWIW似乎最初导致此问题的合法错误已在Kotlin 1.5.0中修复。有关详细信息，请参阅KT-45853(">JVM/IR：从Java接口继承Throwable.getCause引起的意外覆盖"(。。。下面的Kotlin类编译&据我所知：

import com.fasterxml.jackson.annotation.JsonIgnore
import java.net.URI
import org.zalando.problem.AbstractThrowableProblem
import org.zalando.problem.Exceptional
import org.zalando.problem.Status
class BadRequestAlertExceptionKt(
type: URI = URI.create("about:blank"),
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
}
}
@JsonIgnore
override fun getCause(): Exceptional? = super.cause
}