Constructor parameter is null when referred to in an overrided method - spring-boot

Question

My code is written in Kotlin. I have a config class defined in a file along 2 more classes as below:
#Configuration
class MultipartConfig(private val multipartProperties: MultipartProperties) {
#Bean
fun multipartResolver(): StandardServletMultipartResolver {
val multipartResolver = MultipartResolver(multipartProperties)
multipartResolver.setResolveLazily(this.multipartProperties.isResolveLazily)
return multipartResolver
}
}
class MultipartResolver(private val multipartProperties: MultipartProperties) :
StandardServletMultipartResolver() {
override fun resolveMultipart(request: HttpServletRequest): MultipartHttpServletRequest {
return MultipartHttpServletRequest(multipartProperties, request)
}
}
class MultipartHttpServletRequest(
private val multipartProperties: MultipartProperties, request: HttpServletRequest
) : StandardMultipartHttpServletRequest(request, multipartProperties.isResolveLazily) {
override fun handleParseFailure(ex: Throwable) {
val msg = ex.message
if (msg != null && msg.contains("size") && msg.contains("exceed")) {
throw MaxUploadSizeExceededException(multipartProperties.maxFileSize.toMegabytes(), ex)
}
throw MultipartException("Failed to parse multipart servlet request", ex)
}
}
When I debug this code, in the class MultipartHttpServletRequest, constructor property multipartProperties is NOT null but the same property in the throw MaxUploadSizeExceededException(multipartProperties.maxFileSize.toMegabytes(), ex) is ALWAYS null. I cannot understand why this is happening.
Could someone please explain why this is happening?

Answer 1

I'm just answering my own question for clarity. I figured out the issue. It was related to the constructor of that class StandardMultipartHttpServletRequest. Below is the code of the constrcutor.
public StandardMultipartHttpServletRequest(HttpServletRequest request, boolean lazyParsing)
throws MultipartException {
super(request);
if (!lazyParsing) {
parseRequest(request);
}
}
Now, inside of parseRequest there is a catch block (for brevity I'm not posting the whole code of the method)
catch (Throwable ex) {
handleParseFailure(ex);
}
When the constructor of the super class is throwing exception the child's constructor will not get a chance to initialize.