I have folowing entety. One of the fields called file is to upload the document. And the controller function for this is as follows: But then I try to upload file and submit a form I am getting this exception Failed to convert property value of type ‘org.springframework.web.multipart.support.StandardMul…
Tag: java
Java does not catch exception
I am trying to implement lambda expression for constructor. My constructor can throw an IllegalArgumentException. I tried different ways. First way is just calling lambda expression: It works perfectly fine, I can catch Exception and then parse it. The problem occurs when I try to use my own interface: and th…
Cold streams and publishers, is the Garbage Collector fully aware of its true death?
When instanceSubscriptorManager is unable to receive any more boolean values, the last thing to be performed will be a false as isActive, removing localConsumer from publisher. How is localConsumer “aware” that instanceSubscriptorManager will be unable to receive an isActive -> true (again) som…
ClassCastException on raw functional interface lambda invocation
Consider this example: The last line will give java.lang.ClassCastException: class java.lang. Object cannot be cast to class java.lang.String. This is not a surprise for me, as Function is declared to accept String. I know that raw types can give ClassCastException, but all examples I saw are about ClassCastE…
Unboxing may produce Null Pointer Exception after checking if key exists in Map
Android Studio gives the warning: Unboxing of ‘idCollisonMap.get(currentId)’ may produce ‘NullPointerException’ even though I am checking if the key exists before I perform the Map.get(). Am I actually in danger of running into a null pointer exception? My understanding is that .contai…
Should I use GET or PATCH for requesting info while also updating the resource [closed]
Closed. This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 1 year ago. Improve this question I am making a Blackjack service in Java using Spring, and i have metho…
Multiple instances of a bean of one class filled with values from application.properties
I intend to write some HealtCheckContributors for a Spring Boot application using spring-boot-actuator. Hence, I implemented two of them. they are intended for checking the health of different apps, of course, but have a nearly identical structure, except the configuration properties, … SonarQube compla…
Inplementing boolean values [closed]
Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed last year. Improve this question I am trying to make the code more efficient, but don’t know how to apply it in my code. …
Convert Flux into Flux
I am working on spring webflux file upload. From the controller I want to upload the file on amazon S3 bucket. So in the controller I received following object And from the FilePart.content() I can get My question is how can I convert this Flux<DataBuffer> into Flux<ByteBuffer>. I mean into the fo…
Correct way to decrement an AtomicLong by a certain delta
Given an AtomicLong object, what is the right way to decrement the value by a delta? Option 1 Option 2 While both give the desired result, I want to understand under what circumstance will they not represent the desired behavior i.e to decrement a long value atomically? (One drawback of the second approach fo…