Reversing a string is a common task in Java programming, and there are several ways to accomplish this. In this tutorial, we’ll explore four different methods for reversing a string in Java, using the StringBuilder class, the for loop, recursion, and a character array. We’ll provide examples of each method and explain how they work.…
Read More Reverse a String in JavaWorking with strings is a fundamental aspect of programming, and Java provides a rich set of tools and methods for manipulating strings. One common task when working with strings is to remove whitespace characters such as spaces, tabs, and newlines. There are several ways to accomplish this in Java, including using the replaceAll() method from…
Read More Removing Whitespaces in Java StringsConvert char to String in Java using the String.valueOf() method There is a valueOf() static method in the String class that returns the String representation of its argument, which can be a char or any other data type. public class Test { public static void main(String[] args) { char ch = ‘a’; String str =…
Read More Convert Char to String in JavadataType[] arr; Where: int[] intArray = new int[5]; String[] arr = new String[3]; arr[0] = “value 1”; arr[1] = “value 2”; arr[2] = “value 3”;
Read More How to Declare an Array in Java?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 Javapublic 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 JavaWant to learn how to merge two ArrayLists in Java? In this post, we will cover the following ways: Using the List.addAll() method Using the Java 8 Streams Using the ListUtils.union() method Merge two ArrayLists in Java using the List.addAll() method There is addAll() method from the List interface that appends all of the elements in…
Read More How to merge two ArrayLists 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. In…
Read More Serialize and Deserialize an ArrayList in JavaNeed 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 JavaIn this post, you will learn to create a Singleton class in Java. Let’s first see what Singleton class is. What is a Singleton class in Java? A Singleton class in Java is a class that can have only one object at a time. Singleton’s purpose is to control object creation. We can ensure that only one…
Read More Create a Singleton class in JavaIn 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 the…
Read More Sort ArrayList in descending order in JavaWant 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 StringThere are multiple ways to convert a String to an array in Java. We can convert it to a char array or String array. Convert a String to a char Array The String class, a fundamental data type in Java, has the useful toCharArray() method that enables the conversion of a String to a char array.…
Read More Convert a String to an Array in JavaIn this post, you will learn to check if a String contains only digits in Java. We will cover two methods: Using the Character.isDigit() method Using the Integer.parseInt() method Check if a String contains only digits in Java using the Character.isDigit() method In this example, we use a for loop to iterate over the elements…
Read More Check if a String contains only digits in JavaWe often need to compare two ArrayList in Java. In this post, you will learn how to do that in two ways: Using the ArrayList.equals() method Using the CollectionUtils.isEqualCollection() method Compare two ArrayList in Java using the ArrayList.equals() method The ArrayList.equals() method compares two ArrayList. It compares the sizes of the lists, elements equality, and the…
Read More Compare two ArrayList in Java