All Questions
925 questions
1
vote
3
answers
101
views
Can an object belong to both an array and arraylist simultaneously in Java?
I am struggling to write a code sample where an object can belong to an array and arraylist simultaneously and where modifying in arraylist or the array changes the object? See example where I was ...
- 13
-1
votes
1
answer
56
views
Why is the second instantiation of the Player object rewriting the first in this Java program?
I am attempting to write a program that will allow a user to input four characteristics of a "Player" object and add that object to an array list of other Player objects. However, it seems ...
0
votes
1
answer
395
views
Mooc.fi Java 1 -Part07_07 Recipes
(Apologies for the formatting this is my first post)
I am looking at teaching myself Java through mooc.fi Java from the university of Helsinki,
I have been attempting this problem for 4 days straight ...
0
votes
4
answers
203
views
Do I need unique names for all my objects in a list?
I am a first year Comp Sci student. For part of an assignmentI have for my Java class. I need to create a deck class that is an ArrayList containing Card objects.
Here is an example of a card object I ...
2
votes
3
answers
74
views
Split an List of objects based caseNumber into a new List of objects
I have an List of Messages objects. My message object consist of sender and CaseNumber. A SQL query is pulls all the messages into a list. In this list I have multiple of the same CaseNumber.
What ...
- 35
-1
votes
1
answer
72
views
How to add objects to list without having array brackets
I have a for loop in which I add some attributes to the object and at the end I need to have a string (to pass it as a query parameter)
I need
{"items":[{"itemsCode":"item1&...
- 17
0
votes
4
answers
891
views
Difference between Array and ArrayList<> in Java in terms of memory allocation?
I came accross an article which had a question-
Contiguous memory locations are usually used for storing actual values in an array but not in ArrayList. Explain.
https://www.geeksforgeeks.org/java-...
- 686
0
votes
1
answer
19
views
Trying to Compute the differences in two different ArrayLists of Objects with Instance Fields of Type Integer[JAVA]
package pckg;
import java.util.ArrayList;
import java.util.HashMap;
public class Tester
{
public static void main(String[] args)
{
ArrayList<TesterObj> my_first_objects = new ...
- 35
-2
votes
1
answer
3k
views
How to display a list of objects as a JList in java swing?
We are asked to build a system in Java Swing no drag and drop and I cannot understand how to display a list of objects in a JList.
I have a GUI class that creates a JFrame, JPanel, and an empty JList ...
- 3
0
votes
3
answers
1k
views
How to get data from List<Object[]> using java 8
Trying to get a data from DB using JPA. My Data format was like [[John,Wick,New York],[Walter,White,New Mexico]]
And am using below code the get the data from List<Object[]> and with iteration ...
- 233
0
votes
1
answer
79
views
Referencing an interface from ArrayList
I am having trouble understanding ((Edible)objects[i]).howToEat() at line 7 in the java code example given below. Edible is an interface which contains abstract method howToEat() and I understand that ...
-1
votes
2
answers
79
views
Java - from Array to linked ArrayList why it doesn't affect all int values?
I am studing Java, i have simple Array linked to ArrayList, it is fixed size i can change values inside array or list without change length.
So i tried to change all elements of the Array to see ...
- 25
0
votes
1
answer
40
views
how to return numbers by column from objects that have array list attribute
I have a class where I am creating different "Processes", an attribute of this class is an linked list of Integers. I have created different class objects and to make it easy to loop through ...
- 13
0
votes
2
answers
382
views
Java.lang.NumberFormatException when trying to read in a file, so I can use the data with my objects
I keep getting this error when I'm trying to read in a file and add the data to my objects. Can someone please help me? Here is the error:
Exception in thread "main" java.lang....
0
votes
1
answer
64
views
JAVA Attribute of ArrayList<Object> not returning values
Class Hospital
package app;
import java.util.ArrayList;
import app.Department;
public class Hospital {
String hospitalId;
String hospitalName;
int departmentCount;
ArrayList<...
- 83