This post will discuss how to convert a list to a set in Java. As the set collection contains no duplicate elements, it will discard any repeated elements in the list. There are three general-purpose implementations of theSetinterface provided by JDK —HashSet,TreeSet, andLinkedHashSet. This...
In Java, it is common to work with arrays and lists, and sometimes we need to convert an array into a list for easier manipulation and flexibility. An array can be converted to a List easily using multiple ways. Why Convert an Array to a List? Converting an array to a list allows us...
Here, we use thekeySet()method to get keys by creating an array list from a set returned by a map. Check out the following example, which converts a map into a list. Example 1: packagemaptolist;importjava.util.HashMap;importjava.util.List;importjava.util.Map;importjava.util.stream.Col...
converting between a list and a set in java how to convert between a list and a set using plain java, guava or apache commons collections. read more → 2. sample data structure first, we’ll model the element: public class animal { private int id; private string name; // constructor/...
By calling Boolean.toString(flag), we convert this boolean into a string, which is then stored in the variable result. This method is equally straightforward and enhances code clarity, especially when working specifically with boolean values. It’s a great choice when you want to emphasize that...
SinceJava version 1.8, we can haveStreamsand collectors to convert aListinto aMapby usingtoMap()method. Map<Integer,Employee>employeeMap=uniqueEmployeeList.stream().collect(Collectors.toMap(Employee::id,Function.identity())); If we use duplicate employees list thentoMap()method riseIllegalStateExcept...
To convert an array to a Set in Java, you can use the Arrays.asList() method to create a List from the array, and then use the List.toSet() method to create a Set from the List. Here is an example of how to convert an array to a Set: import java.util.Arrays; import java....
import java.util.Arrays; public class Demo { public static void main(String[] args) { Arrays.asList(20, 50, 100, 200, 250, 300, 500, 550, 600, 700) .stream() .filter(val -> val > 400) .map(val -> "Value greater than 400 = " + String.valueOf(val)) .forEach(val -> Sy...
Set<String>keySet=map.keySet(); 4. Conclusion This tutorial taught us how to convert Java Map keys and values into an Array, List or Set with simple examples. We learned to use theArrayListandHashSetconstructors as well as Stream APIs. ...
Write a Java program to convert an ArrayList to an array and remove null values in the process. Write a Java program to convert an ArrayList containing duplicate values into an array without duplicates. Write a Java program to convert an ArrayList of objects to an array of a specific type....