Java Examples

class PrintArrayElementsExample { public static void main(String[] args) { int[] arr1 = {1, 7, 9, 5, 2, 8, 3}; String[] arr2 = {“Megan”, “Tom”, “Melissa”, “John”, “Steve”}; // print elements of the arr1 System.out.println(Arrays.toString(arr1)); // print elements of the arr2 System.out.println(Arrays.toString(arr2)); } } Output: [1, 7, 9, 5, 2, 8, 3] [Megan, Tom, Melissa, John,…

Read More Print Array Elements in Java

public class SplitString { public static void main(String[] args) { String names = “Tom,Steve,John,Megan,Melissa”; // split string String[] arr = names.split(“,”); // print the size of the array System.out.println(arr.length); // print the elements Stream.of(arr).forEach(System.out::println); } } Output: 5 Tom Steve John Megan Melissa   If you need a list, instead of an array, use the…

Read More Split a comma-separated String in Java

class CheckIfArrayContainsValue { public static void main(String[] args) { String[] programmingLanguages = {“Python”, “Kotlin”, “Ruby”, “JavaScript”, “C#”, “Java”, “Flutter”}; for (String lang : programmingLanguages) { if (lang.equals(“Java”)) { System.out.println(“It does contain!”); break; // value found, exit the loop } } } } Output: It does contain!   Here, we are iterating over the array, and…

Read More Check if Array contains a value in Java

import java.io.ByteArrayInputStream; import java.io.InputStream; import java.util.*; class ConvertInputStreamToString { public static void main(String[] args) { String resultString; String str = “Some String”; // create InputStream using the bytes from the above String InputStream inputStream = new ByteArrayInputStream(str.getBytes()); // Convert data from InputStream into a new String try (Scanner scanner = new Scanner(inputStream).useDelimiter(“\\A”)) { resultString =…

Read More Convert InputStream to a String in Java

<dependency> <groupid>org.apache.poi</groupid> <artifactid>poi-ooxml</artifactid> <version>5.0.0</version> </dependency> import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; @Data @AllArgsConstructor @NoArgsConstructor public class Product { private int id; private String color; private String size; private int cost; private String description; } import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.ss.usermodel.Sheet; import org.apache.poi.ss.usermodel.Workbook; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.util.ArrayList; import…

Read More Read and write Excel files in Java

In this post, you will learn how to Serialize and Deserialize an ArrayList in Java using the FileOutputStream and FileInputStream classes. How to Serialize an ArrayList in Java? Serialization is the process of changing the state of an object into a byte stream. For example, we use it to write some Java objects into a file.…

Read More Serialize and Deserialize an ArrayList in Java

Need to remove a character from String in Java?  You can do that by converting the String to a StringBuilder class and using the deleteCharAt() method that removes the character at a specified position. Example class Test { public static void main(String[] args) { String str = “Learn Java”; str = new StringBuilder(str).deleteCharAt(5).toString(); System.out.println(str); }…

Read More Remove a Character from String in Java

In one of the previous examples, we covered how to sort an ArrayList in ascending order. In this post, you will learn how to sort ArrayList in descending order in Java. We will explore the following ways: Using the sort() method Using the Collections.sort() and Collections.reverse() methods Sort ArrayList in descending order in Java using…

Read More Sort ArrayList in descending order in Java

Want to learn how to count character occurrences in Java String? Below is the program that uses a Map to store chars as keys and the number of occurrences as values. class Test { public static void main(String[] args) { String str = “moiujjmhrqdoasdsooqavvae”; Map<Character, Integer> map = new HashMap<>(); for (int i = 0;…

Read More Count Character occurrences in Java String