What is a proper usage of the thenComparing function and why this option is not working properly? I dont quite understand the errors that are thrown… Error: no instance(s) of type variable(s) U exist so that Object conforms to Comparable<? super U> cards.stream() .collect(Collectors.groupingBy(card -> card.kind.rank, Collectors.counting())) .entrySet().stream() .sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()).thenComparing(Map.Entry::getKey)) .forEachOrdered(e -> sortedCards.put(e.getKey(), e.getValue())); My card… Read More thenComparing function throws 'no instance(s) of type variable(s) U exist so that Object conforms to Comparable<? super U>'

How to get rid of the error "erasure of method is the same as another method in type" without changing methods name public static List<String> convert(List<String> list, Function<String, String> convertFunction) { return list; //proper code } public static List<Map<String, String>> convert(List<Map<String, String>> list, Function<String, String> convertFunction) { return list; //proper code } >Solution : You… Read More Java – erasure of method is the same as another method in type

my responses may be slow, but I had a design question I’m hoping to get some advice on: I’m trying to make a fight simulator for a phone game I play. I have a class representing each hero, which implements their particular abilities’ logic. They inherit an abstract Hero class, which itself inherits an abstract… Read More Design question about instantiating objects in Java

How to output an element (content of index) that has been repeated by the user input multiple times with out using the collections, hashmap or treemap method? I am looking for a linear or you could say a mathematical approach rather than a ready command approach, could someone help please? import java.util.ArrayList; import java.util.Scanner; Scanner… Read More How to output an element that has occured or listed multiple times in an array list from a user input

This is the Code: private List listaPunktowInt(List lista) { String liniaString=""; List<Integer> list=new ArrayList(); Iterator<String> it=lista.iterator(); while(it.hasNext()) { liniaString=it.next(); if(Pattern.matches("\\d*",liniaString)) { list.add(Integer.parseInt(liniaString)); } } //Collections.sort(list); //Collections.reverse(list); System.out.println(list); return list; } Input:[56, 4, 2 2022 04 06, 1, 1, 1] Output:[56, 4, 1, 1, 1] I want "2" to be included as well but the rest… Read More Can I ignore rest of the list when the pattern occurs java?

Since we are able to implement many interface such as Runnable why hasn’t Java deprecated the Thread class yet? >Solution : Extending the Thread class is not recommended. But deprecating a class indicates that it shouldn’t be used at all. And Thread is still useful as a standalone class. It’s just that the way we… Read More Why Thread class is not deprecated by Java

I am trying to convert the below unix cmd line arg to windows: java -Xms5g -Xmx20g -XX:MaxPermSize=5g -classpath "/home/user/software/client/lib/*:/home/user/software/client/resources" com.perf.startup.Tool -user admin -password password123 -env testEnv I have tried this for Windows: java -Xms5g -Xmx20g -XX:MaxPermSize=5g -cp "C:\user\software\client\lib\*" "C:\user\software\resources" com.perf.startup.Tool -user admin -password password123 -env testEnv However I get this Error: Error: Could not find… Read More Convert unix java cmd line arg to windows

There are three glasses with juice of amount A, B and C units. I have another small empty glass which can hold 1 unit of juice. Using this small glass I can take 1 unit of juice from one glass and pour it to another glass. Can you figure out if they will go to… Read More How to Equal 3 Glass of Juices with one Extra unit? What is wrong in my code?

int n = 10; int n1 = ~n; System.out.println(Integer.toBinaryString(n)); // 1010 but, maybe 00000000 00000000 00000000 00001010 System.out.println(n); // 10 System.out.println(Integer.toBinaryString(n1)); // 11111111111111111111111111110101 System.out.println(n1); // -11 How does 11111111111111111111111111110101 output as -11? I couldn’t find a way to convert the complement back to decimal >Solution : The two’s complement is used for negative numbers -n… Read More Why is the 1's complement of decimal 10 printed as -11 in Java?

I have been building program, where a. teacher is asked for information of 5. students and all the inputs should be saved after to a txt. file. Although my file is always created but is always empty… Could someone please help me find my mistake ? import java.util.Scanner; import java.io.PrintWriter; import java.io.IOException; public class programming_project_1… Read More Saving Inputs to txt. file in Java