You can write an ArrayList object values to a plain text file in Java by using the built-in java.nio.file package. First, create your ArrayList object and add some values to the list as shown below: List arrList = new ArrayList<String>(); arrList.add("Java"); arrList.add("Programmi...
In this tutorial, you will learn how to initialize an ArrayList in Java. There are several different ways to do this. Let’s discuss them with examples. 1. Basic (Normal) Initialization One of the ways to initialize anArrayListis to create it first and then add elements later usingadd()m...
Use thedistinct()Method in theArrayListto Find Unique Values in Java Use theHashSetto Find Unique Values in Java In Java, theArrayListcan’t prevent the list that contains any duplicate values. But sometimes, we need to extract only the unique values for numerous purposes. ...
toArray() method is available in java.util package. toArray() method is used to return a converted Array object which contains all of the elements in the ArrayList. toArray() method does not throw any exception at the time of conversion from ArrayList to Array. It's not a static method...
However, it’s not without its limitations. TheCollections.sort()method sorts in ascending order by default, and it can’t handle null values. If you try to sort a list with null values, it will throw aNullPointerException. Moreover, it may not work as expected with custom objects, unle...
import java.util.Map; import java.util.Map.Entry; public class CrunchifyHashmapToArrayList { public static void main(String... args) { HashMap<String, Integer> companyDetails = new HashMap<String, Integer>(); // create hashmap with keys and values (CompanyName, #Employees) companyDetails...
The last method in this list is overriding atoString()method inside theModelClass. This function will return thenamewhen we call it usingmodeList. Take note that this process can only return string values, as implied in its name. importjava.util.ArrayList;importjava.util.Arrays;importjava.util...
In this program, we aresorting the given ArrayList in descending order. To sort an ArrayList in descending order, we need to passCollection.reverseOrder()as a second parameter in theCollections.sort()method as shown below. The same way, we can sort an ArrayList of integer type in descending...
In this tutorial, you will learn how to remove element from Arraylist in java while iterating using different implementations provided by Java. It is necessary to understand the right way to remove items from a List because we might encounter errors in our programs if not done correctly. For...
It’s been long time I’ve been playing with JSONObject,JSONArrayand more. In this tutorial we will go over steps on how to convertJava ArrayListto JSONObject. We will useGoogle GSONutility for the same. Just include below dependencies to your JavaEnterprise projectand you should be good....