All Questions
26,476
questions
1
vote
2
answers
57
views
How to add an ArrayList in a Superclass using Getters and Setters from a subclass
Here is the super class:
public abstract class ImperialCluster implements Serializable,Clusterable {
private static final long serialVersionUID = 1L;
private String clusterType;
...
-1
votes
1
answer
37
views
How to filter objects from list based on uniqueness of object property?
I have a list of Person objects. Each Person object has an int id property, along with some others. Currently my list of Person objects has multiple objects with the same id. I want to filter the list ...
- 423
-1
votes
0
answers
29
views
Java add method is not working during arraylist iteration [duplicate]
Add method is not working in Iteration of arraylist but remove method is working in iteration of arraylist.
package thread;
import java.util.ArrayList;
import java.util.Iterator;
import java.util....
-3
votes
1
answer
31
views
Previous objects in the list of objects are getting modified on adding the last object to the list [duplicate]
Why the previous objects get updated when last element is added in the list?
I am creating the objects inside the loop, setting their properties, adding them to their list.
But upon adding the last ...
-1
votes
0
answers
27
views
How to see if arraylist of a class contains a specific value [duplicate]
I am working on a java project, I have an ArrayList of a custom class with two variables (a boolean and char) I need to check if it contains a specific char. How do I get it to check the char of it.
...
-1
votes
4
answers
83
views
ArrayList sublist method clarification
This is regarding the usage of subList method in an ArrayList.
Consider I am having an array as below:-
int[] prices = {71,11,65,99,21,82};
I am converting the above array to arrayList as below:-
...
- 61
0
votes
0
answers
26
views
How do I fix this nullPointException exception in my program? [duplicate]
I'm trying to create a simple card game where the user faces against a computer (which is a class in my method that takes its turn automatically after the user), but I'm encountering a ...
-1
votes
1
answer
114
views
Performance of ArrayList<Integer> versus int[]
I have a million ints that I want to store in a data structure. I wanted to know whether the int array (int[]) is any more efficient than an ArrayList. Are there any performance gains to using int[] ...
- 12k
-4
votes
1
answer
64
views
Why is my code giving wrong answer when using 2d ArrayList and passing when using 2d arrays?
Here is the DP question,
Given a ‘N’ * ’M’ maze with obstacles, count and return the number of unique paths to reach the right-bottom cell from the top-left cell. A cell in the given maze has a value '...
-1
votes
2
answers
42
views
Type mismatch: inferred type is OnSuccessListener<ArrayList<myClass?>> but OnSuccessListener<in ArrayList<myClass>!> was expected
I am trying to convert Java code to Kotlin code but in a code segment in particular it seems is not posible to fully convert.
I am getting a Build error:
Type mismatch
Required: OnSuccessListener<...
- 113
0
votes
1
answer
72
views
enum float problem calculating price of coffee [closed]
package Main;
import java.util.ArrayList;
import java.util.List;
public class Main {
List<Ingredients> ingredients = new ArrayList<>();
public enum Ingredients {
...
1
vote
3
answers
124
views
Which List implementation does Kotlin use when calling listOf()
As known, in Java List is not a class, but an interface, so you can't get an instance of a List, you have to specify the implementation, like ArrayList, LinkedList, etc. So here is the question: which ...
0
votes
1
answer
49
views
how to connect a Arraylist to one Index from an another Arraylist
im a bigginer for coding and java. Im now learning about Hashtable.
What im struggling here ist to connect a ArrayList to one of the index from an another ArrayList.
a simple image of what I want to ...
0
votes
1
answer
72
views
Undeclared variable when trying to use get() on Arraylist
I am trying to filter out specific elements of my array list but I keep getting an undeclared variable error.
public class Student
{
private String name;
private int age;
private double ...
0
votes
1
answer
80
views
making a simple calculator but the input is in one line (newbie)
package kotauto;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;...
