logo
Tags down

shadow

Array sort not working, no instance(s) of variable(s) T exist so that Employee conforms to Comparable


By : Jwd
Date : September 15 2020, 11:00 AM
I hope this helps you . You need to implement Comparable interface and override its compareTo method like following:
code :
public class Employee implements Comparable<Employee> {
    String name;

    public Employee(String name) {
        this.name = name;
    }

    public String toString() {
        return this.name;
    }

    @Override
    public int compareTo(Employee employee) {
        return this.name.compareTo(employee.name);
    }
}
Comparator<Employee> employeeNameComarator = new Comparator<Employee>() {
    @Override
    public int compare(Employee employee1, Employee employee2) {
        return employee1.name.compareTo(employee2.name);
    }
};
Collections.sort(listOfEmployees, employeeNameComarator);


Share : facebook icon twitter icon

No instance of type variable V,K exist so that HashMultiMap<V,K> conforms to MultiMap<..,..>


By : IllusionalQuestions
Date : March 29 2020, 07:55 AM
it should still fix some issue check your imports and class/interface names: MultiMap and HashMultimap should be imported from the same framework.
For instance Apache Collections has MultiMap and Guava has Multimap - typo and wrong import is likely to happen.

No instance(s) of type variable(s) U exist so that Optional<U> conforms to Response


By : Ojsmith
Date : March 29 2020, 07:55 AM
it fixes the issue Based on the error, the return type of your method is Response. However, update(resourceID, data).map(updatedResource -> Response.status(Response.Status.OK).entity(updatedResource).build()) returns an Optional, so you have to change the return type to Optional.
So the method would look like this:
code :
public Optional<Response> yourMethod (...) {
    return update(resourceID, data).map(updatedResource -> Response.status(Response.Status.OK).entity(updatedResource).build());
}
public Response yourMethod (...) {
    return update(resourceID, data).map(updatedResource -> Response.status(Response.Status.OK).entity(updatedResource).build()).orElse(defaultValue);
}

When using Collections.sort - no instance of Variable T exist so that Collection conforms etc


By : Stephen
Date : March 29 2020, 07:55 AM
I hope this helps you . As per request, here's a compilation of my comments to answer the question:
The immediate problem is that Collections.sort(List) takes a List parameter and not just a Collection because collections in general don't have to be sortable (e.g. hash sets aren't). Additionally the method returns void and sorts the passed list in place, i.e. the way you call it won't compile.
code :
public class GenreManager{
   private List<Genre> genres;
   ...

   public GenreManager(Collection<Genre> genres){
     ... 

     //create a list out of the passed collection
     this.genres = new ArrayList<Genre>( genres );

     //sort the list    
     Collections.sort(this.genres);
   }
}
public class GenreManager{
   private SortedSet<Genre> genres;
   ...

   public GenreManager(Collection<Genre> genres){
     this.genres = new TreeSet<>( genres );
   }
}
public GenreManager(Collection<Genre> genres){
  this.genres = new TreeSet<>(); //the generic type is inferred from this.genres

  for( Genre element : genres ) {
    //If the element didn't exist in the set add() will return true, false if it existed  
    boolean nonDuplicate = this.genres.add( element );

    //handle the duplicate element here
  }
}

no instance(s) of type variable(s) U exist so that Foo conforms to CompletionStage<U>


By : Shawn Zhang
Date : March 29 2020, 07:55 AM
seems to work fine The last thenCompose in the chain should be thenApply. The function passed to it is returning a GetUsersForAdAccountResponse which is not CompletionStage.
thenCompose is the flatMap of CompletableFuture. It takes a function that returns a CompletionStage and flattens the result.

No instance of type variable(s) T exist so that ID conforms to Comparable<? super T>


By : nielsAD
Date : March 29 2020, 07:55 AM
This might help you This error means the elements in the parameter Collection of method Collections.max should implement interface Comparable. So it can use the compareTo to find the max elements in the Collection.
You can make it compile by declaring it this way:
code :
public abstract class AbstractMapService<T, ID extends Comparable<ID>> 

private ID getNextId() {
    return Collections.max(map.keySet());
}
public abstract class AbstractMapService<T> {

    protected Map<Long, T> map = new HashMap<>();

    Set<T> findAll(){
        return new HashSet<>(map.values());
    }

    T findById(Long aLong) {
        return map.get(aLong);
    }

    T save(Long aLong, T object){
       map.put(aLong, object);
       return object;
    }

    void deleteById(Long aLong){
        map.remove(aLong);
    }

    void delete(T object){
        map.entrySet().removeIf(entry -> entry.getValue().equals(object));
    }

    private Long getNextId() {
        return Collections.max(map.keySet()) + 1L;
    }
}
Related Posts Related Posts :
  • IBM Maximo Java API - Cannot filter MboSet by related attribute
  • Java: Multi Key/Value Map
  • Bank Account class with deposit and withdraw
  • Java memory model: single thread and multi-core CPU
  • Track users activities on a Spring web app
  • Adding a Log4j logging to a Vaadin 8 application
  • How to reverse an array without a loop or creating new array
  • Overriden readObject() reading object correctly and then making all member variables null/default value
  • How to get the LIs seperate from the UL in Selenium
  • Akka: - why is it that messages are not guaranteed to arrive (after being send)? What is the failure rate for messages?
  • Cucumber exception when run the test
  • Why do I have Java 11 in Intellij terminal?
  • How to improve performance while calculating matrix sum
  • Time complexity question asked in interview
  • Whats difference between dependency management and build management tool?
  • How to sort an infinite Flux?
  • Get all the logs as HTTP response in Spring Boot
  • Converting list of objects to key value pair in java
  • Is it possible to skip itteration in java, when you are using method in that loop?
  • Difference between KStream mapValues and transformValues
  • return List<object> from view of @Query in spring boot
  • Maven dependency with older spring boot version
  • Java: alternative to null for special meaning
  • Annotation proccessor configuration from a Gradle multi module build in IntelliJ 2019.3 seems not to work correctly
  • Java: convert List<List<String>> into List<List<Double>>
  • Android Studio Java - shopping cart app, totalling problems
  • java.lang.IndexOutOfBoundsException in java
  • Why is my java while loop continue printing with true status?
  • Maven concatenate text files at compile phase
  • How to debug Java HTTPS cert validation
  • Adding an external jar file to an OSGi application causes issues
  • Java Encoding issue
  • Regexp finding substring with conditions
  • Sorting an array by its values based on two arrays
  • java.sql.SQLException: Column 'Max(category_id' not found
  • Will the java Supplier returns same object at any situation
  • Annotations size smallest than real size in database
  • Infinispan Soft Index File Store OutOfMemoryError after upgrade to 10.0.1.Final
  • Java regex to add space after closing tag if its not present
  • Is there a way making python produce the same result bit-wise shift left with java?
  • I want to change this line JAVA to kotlin
  • Why does songName[i]!= null evaluates to T when it should be F
  • In Spring, is it better practice to return a ResponseEntity directly from the service or should i create it inside the c
  • How to display a message in TestNG report (for passed test cases)
  • Get tag's related BBox's even though there is no attributes (/A in document catalog structure) related to Layout in PDFB
  • Why doesn't it work finding index in Array
  • Event class changes with Axon CQRS
  • Java 8: How can I check if all the fields of an object are NULL except from one
  • Why doesn't Hibernate fully resolve my object when returning it from a @Transactional method (Spring boot)?
  • How to initialize a range array of long-s in Java?
  • When exacty is the object initialized?
  • AEM Sling Resource Resolver Mapping Methods
  • How do I automate my webdriver to take data from excel sheet and use launch it?
  • The fastest way to check if two lists contain the same object
  • How to deploy SpringBoot project on Heroku?
  • Java: one field of three possible types?
  • Can't read slash ( / ) with Scanner Java
  • How to get only the digits from list of string using java
  • LoginActivty Template for Android Studios (the most current version) Need to verify username and password before going o
  • Does Lambda completely demolish the usage the anonymous inner class from java 8?
  • shadow
    Privacy Policy - Terms - Contact Us © 35dp-dentalpractice.co.uk