thenComparing function throws 'no instance(s) of type variable(s) U exist so that Object conforms to Comparable<? super U>'

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>'

Java – erasure of method is the same as another method in type

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

How to output an element that has occured or listed multiple times in an array list from a user input

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

Can I ignore rest of the list when the pattern occurs java?

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?

Convert unix java cmd line arg to windows

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

Why is the 1's complement of decimal 10 printed as -11 in Java?

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?