I am learning C and debugging code for spell checking a chosen .txt file. My last hurdle here is the load function of my hashmap. It successfully reads a given word from a dictionary file, stores it, assigns it to a temp node , but the problem comes when I try to make my struct… Read More When creating loader for hashmap, my bucket points back to itself
I’m trying to define a Map<String, DataTablesRepository> to map more than one JPA repository. This is my code @Service @AllArgsConstructor public class MyDataTablesService { private final RegistroDtRepository registroDtRepository; private final ContinentiDtRepository continentiDtRepository; public Map<String, DataTablesRepository> repositories = this.createMap(); public DataTablesOutput<?> findAllDatatable(String repoId, DataTablesInput input) { System.out.println(this.repositories); DataTablesRepository repository = this.repositories.get(repoId); DataTablesOutput<?> res = repository.findAll(input); return… Read More Map<String, Repository> Unexpected beheaviour
Here is a example: import java.util.HashMap; class Main { public static void main(String[] args) { HashMap<Integer, Integer> a = new HashMap<Integer, Integer>(); a.put(1,2); a.put(2,5); Object b = a; // Do something here to make the variable "b" become a HashMap } } I tried this HashMap<Integer, Integer> c = (HashMap<Integer, Integer>) b; I get this… Read More Convert "Object" to "HashMap" in Java
The signature of HashMap::entry is: pub fn entry(&mut self, key: K) -> Entry<‘_, K, V> Ok, looks good. I want to take an entry from the HashMap whose key is K, so of course I need to give it a K. However, the signature of HashMap:get is: pub fn get<Q>(&self, k: &Q) -> Option<&V> where… Read More Why does HashMap::get and HashMap::entry take different types of key?
I have been reading https://www.alibabacloud.com/blog/the-clever-design-of-java-map_597979 for the internal implementation of the HashMap and CHM. There is an interesting line for which I could not find more explanation for : Can someone point me to the bug this refers to? I could only find the bug related to HashMap improvement with RB-Trees, but nothing about the… Read More What is the dead loop bug in HashMap in earlier versions?
I’ve a list of payloads and a payload looks like Payload { public int id; public String name; public String foo; public List<String> list; } now I want this to a HashMap where the key is a value of the list property, like payloads = [ {id:45, name:"Alfred", foo:"bar", list:["AAA", "BBB"]}, {id:2, name:"John", foo:"various", list:["CCC",… Read More Convert list of payloads with a property List<String> to HashMap<String, Payload)
import java.util.*; public class Hash_Map_Demo { public static void main(String[] args) { Map<String, String> toEmails = Collections .singletonMap("key", "Value"); Map<String, String> userEmails = new HashMap<>(); userEmails.put("abc@gmail.com", "abc"); toEmails.putAll(userEmails); } } when i’m trying to run the above code, I’m encountering the following exception Exception in thread "main" java.lang.UnsupportedOperationException at java.util.AbstractMap.put(AbstractMap.java:209) at java.util.AbstractMap.putAll(AbstractMap.java:281) at Hash_Map_Demo.main(Hash_Map_Demo.java:13) I… Read More Hashmap is unable to be added to a collecitons.singletonmap
The purpose and goal of the method is to print the hash map in reverse from <Key, Value> to <Value, Key>. But I’m having a problem on line 7(revrse();) where where I get the error "The method reverse(Map<Integer,String>) in the type lab8_Part3 is not applicable for the arguments ()". All the solutions eclipse suggest result… Read More Having trouble running public HashMap method
I define a Triple class with equals and hashcode method. According the docs,HashSet.contains() method of Java HashSet must returns the same value of Objects.equals(). But contains() method of Java HashSet method return true, when it suppose to be false. class Triple{ private List<Integer> triple; public Triple(int one, int two, int three){ this.triple = new ArrayList<>();… Read More Java HashSet contains method return true when it supposes to be false
In python, I’d use a list of dictionaries to collect data (like name, age, height, etc.) of several people that a user enters, but now I want to do the same thing in Java. Is an array of HashMaps the best way to do that? static List<Map<String, Object>> driverList = new ArrayList<>(); >Solution : You… Read More Array of hashmaps