Use Comparable and Comparator as shown below, you can also visit https://www.journaldev.com/780/comparable-and-comparator-in-java-example for further details. import java.util.Comparator; class Employee implements Comparable<Employee> { private int id; private String name; private int age; private long salary; public int getId() { return id; } public String getName() { return name; } public int getAge() { return age; } … Read more
You have a lot of error in your code : First Don’t ever name your variables with Upper letter in beginning, java use camelCase Second Don’t declare your variable with private public in your method. private ArrayList<Object> List = new ArrayList<Object>(); Third You can’t declare a method inside another method you have to close the … Read more
There are two possbile solutions. The first one is to override the equals method. Simply add: public class DataRecord { […..] private String TUN; @Override public boolean equals(Object o) { if (o instanceof DataRecord) { DataRecord that = (DataRecord) o; return Objects.equals(this.TUN, that.TUN); } return false; } @Override public int hashCode() { return Objects.hashCode(TUN); } … Read more
You can use the .indexOf(Object o) method which returns, as the java 8 documentation specifies: the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element You can also use .lastIndexOf(Object o) which, as you would guess, will return the last occurrence of … Read more
you have two approaches: ArrayList<String> ar = new ArrayList(); ar.add(“UserId”); //adding item to arraylist ar.add(“Directory”); ar.add(“Username”); ar.add(“PhoneNumber”); // approach one using iteration for (Iterator<String> it = ar.iterator(); it.hasNext(); ) { String f = it.next(); if (f.equals(“UserId”)) System.out.println(“UserId found”); } // approach two using a colletion which supports fetching element by key Map<String,String> myMap=new HashMap<>(); for(String … Read more
Introduction If you are looking for a way to get substring items within an ArrayList in Java, then you have come to the right place. In this article, we will discuss how to get substring items within an ArrayList in Java. We will look at different methods of doing this, such as using the subList() … Read more
Exception line (java.lang.ArrayIndexOutOfBoundsException: length=5; index=5) clearly mentions that you are Trying to get index=5but the length of the dato is 5(length=5). So, use only proper index i.e. index 0 to 4. OR Make sure that enough indexes exists to access. Note: You have used dato.split(“, “);. Try with dato.split(“,”);. May be the problem is with … Read more
Look at set1 and compare it to set2 notice that in the second case you specifying exactly what kind of objects set2 will hold but in the set1 you don’t so the compiler has no idea that you using your abc class (By the way class name should start with a capital). Here is the … Read more
Putting your arraylist inside a method means it can only be accessed by the method it is in and is lost when the method is finished running. You have two options. Change the return type of your method as an arraylist and return and manipulate your arraylist Create the arraylist outside of a method global … Read more
If you want to hold on to the original position of the object you need to make a copy of the arraylist before you shuffle it. And then use indexOf solved Arraylist element index before and after Collections.shuffle in java
public static void main(String[] args) { List<String> data = new ArrayList<String>(); String yourRequiredString = “dessert”; data.add(“apple fruit”); data.add(“carrot vegetable”); data.add(“cake dessert”); for (int i = 0; i < data.size(); i++) { if (data.get(i).contains(yourRequiredString)) { System.out.println(i); } } } Hope this helps… solved Find String in ArrayList Containing Phrase
Just make an ArrayList of HashSets : ArrayList<HashSet<Integer>> list = new ArrayList<HashSet<Integer>>(); Then create HashSets, fill them, and put them in your ArrayList normally. HashSet<Integer> set = new HashSet<Integer>(); set.add(1); set.add(whateverIntValue); list.add(set); You can then get the nth HashSet of your list using list.get(n). solved How to make ArrayList of hashset in java? [closed]
after you’ve sorted the director list…. just take one director as an key value in outer loop and then start comparing each and every movie name in inner loop… How can I sort a List alphabetically? this would be helpful… do some searching next time….it is easy to find such solutions… 🙂 😉 3 solved … Read more
In the first example, the loop runs until the pointer itself becomes null, which it never does (instead, it’s eventually incremented past the end of the buffer, whereupon the program exhibits undefined behavior). In the second example, the loop runs until the character pointed to becomes zero – which it does once the advancing pointer … Read more
To add items to a static list you can use the block static{} public class Employee { …. private static ArrayList <String> employeeID = new ArrayList <String> (); static { employeeID.add(“632584”); employeeID.add(“259415”); employeeID.add(“257412”); employeeID.add(“953647”); employeeID.add(“126497”); employeeID.add(“453256”); employeeID.add(“125689”); } … } } Or use constructor public class Employee { …. private static ArrayList <String> employeeID = … Read more