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How To Sort List Of Objects In Java

Last Updated : Mar 11, 2024

How To Sort List Of Objects In Java

In this article we will show you the solution of how to sort list of objects in java, in Java programming, sorting a list of objects is a typical action that enables programmers to meaningfully organize data. A list of objects can be sorted in Java by the value of a particular field.

A compareTo function can be defined by defining the Comparable interface in the object class, or a custom comparison method can be defined by utilizing the Comparator class.

The list can be sorted in either scenario using the Collections.sort method. We'll discuss sorting a list of objects in Java presently.

Step By Step Guide On How To Sort List Of Objects In Java :-

import java.util.*;
class CustomObject {
 private String customProperty;
 public CustomObject(String property) {
  this.customProperty = property;
 }
 public String getCustomProperty() {
  return this.customProperty;
 }
}
public class TK {
 public static void print(ArrayList<CustomObject> list) {
  for (CustomObject obj : list) {
   System.out.println(obj.getCustomProperty());
  }
 }
 public static void sort(ArrayList<CustomObject> list) {
  list.sort((o1, o2)
    -> o1.getCustomProperty().compareTo(
     o2.getCustomProperty()));
 }
 public static void add(ArrayList<CustomObject> list) {
  list.add(new CustomObject("Z"));
  list.add(new CustomObject("A"));
  list.add(new CustomObject("B"));
  list.add(new CustomObject("X"));
  list.add(new CustomObject("Aa"));
 }
 public static void main(String[] args) {
  ArrayList<CustomObject> list = new ArrayList<>();
  add(list);
  sort(list);
  print(list);
 }
}
  1. As you can see, we write Java code here to sort lists of items.
  2. We define two classes, CustomObject and TK, which each have three static methods: print, sort, and add, as well as a main function.
  3. A CustomObject class has a constructor that accepts a String argument & initializes the private instance property customProperty.
  4. The value of customProperty is returned by the getter method getCustomProperty, which is also present.
  5. The static function print in the TK class then prints the value of each element's customProperty when given an ArrayList of CustomObjects as input.
  6. Additionally, the TK class has a static method called sort that accepts an ArrayList of CustomObject as input as well as arranges the list in ascending order according to the value of customProperty.
  7. The TK class additionally includes a static method called add that accepts an ArrayList of CustomObject as input & adds five CustomObject objects with the values "Z", "A", "B", "X," and "Aa" for customProperty to the list.
  8. The main method then generates a new ArrayList of CustomObjects, uses the add method to add five CustomObject objects to the list, then uses the sort method to order the list.
  9. The sorted list is printed using the print method at the end.

Conclusion :-

As a result, we have successfully acquired the knowledge necessary to sort a list of Java objects.

We also discovered how important it is for developers to know how to sort a list of objects in Java because it facilitates the meaningful organization of data.

Java provides two methods for sorting lists of objects: either by implementing the Comparable interface & specifying a compareTo function or by utilizing a Comparator class to define a unique comparison method.

The Collections.sort method can be used to sort the list using either strategy.

An essential skill for understanding Java programming is the ability to sort lists of objects, which can improve the effectiveness and efficiency of data processing.

I hope this article on how to sort list of objects in java helps you and the steps and method mentioned above are easy to follow and implement.

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Experienced Computer Programmer with a broad range of experience in technology. Strengths in application development and Object Oriented architecture design, front end programming, usability and multimedia technology. Expert in coding languages such as C, C++ Java, JavaScript, PHP and more.

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