Exception is : Required type: Mono Provided:Mono no instance(s) of type variable(s) T exist so that Mono conforms to UserDto inference variable R has incompatible bounds: equality constraints: UserDto lower bounds: Mono How to write function getUserInfoByUserId ? Answer Assuming that you are always returning Mono from your repository methods, you can do this I would recommend you to start
Tag: dictionary
Java – Collectors Group By and Expand Map by number of records
I have the following java list of UserRecords objects that are grouped by user_name. I want to be able to break down this list into small batches of 5 records if a user has more than 5 records. Here’s the result of my user group: Since Jane Doe has more than 5 records, I would like her results to be
Upper bounded wildcard as a Map Value – how to provide a default Value with getOrDefault()
I have the following map Sometimes there is a List and sometimes there is a Set as a value. Now I’d like to get value, but there is a problem, it does not compile. I know I can do something like this: But I want to understand how getOrDefault() method is supposed to work with wild-card generics. Answer The short
Adding values to Map from a File
I want to iterate through a file that has key/value pairs and put them into a Map. The file contains values like so: Here is my code: The problem I am having is that the Map called instructions is not adding new values from the file, it stops at size 3, not sure why. Would appreciate some help here. Thanks!
How link multiple keys to the same value in the HashMap
I am trying to link the value of a key to another key’s value but cannot seem to get it working. For example, if I’m creating a HashMap and adding a key-value pair (“x”, 0) to it. I then want to be able to add other keys mapped to the same value as the first one. So if I have
Query did not return a unique result
This is the query I have written: This is the output I am getting from the database: id versions 101 0.0 101 1.0 101 2.0 101 3.0 In my application, I am storing this result in but it gives an error saying “query did not return a unique result” How can I store this result? which data structure could I
HashMap has all the entries changed to last insert for every cycle
I need to insert a key and an element, containing the key and another value (which will be selected in the end from the map sorted by keys) into an HashMap. I decided to lastly convert the HashMap to a TreeMap to sort it, but the HashMap gets filled with data that change at every insert: here is the code
How to get certain values from ArrayList and put them in a map
I have a program where there are 52 cards and int number of players (for example lets start from 4), the task is asking me to put elements like this in a map of Map<String, List>: I have written the logic like this: Any suggestions how to put those List in the map according to the task? Answer Since cannot
Get the last element of each entry in a LinkedHashMap?
I have a map and I want to extract the last value for each key from that map, but I can’t get it: Extract: i.e. the last NUM entries for each key Answer You can use reduce to extract the last value from Map<String,String> and then collect them using toMap into LinkedHashMap to save the insertion order But as a
Create multiple Lists from one (Group List’s Objects by a specific field)
Given that I have the array of : gives me : I want to create a new array which is grouped by the 3rd parameter of surname object. So that my array becomes So that when we do .get(1) we would get object of kasis and samika. Need the help in respective to java 8. I heard that we can