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Articles by karthikeya Boyini
Page 86 of 142
What are annotations in Java?
Annotations are a tag (metadata) which provides info about a program. Annotations in Java Start with the symbol ‘@’. They are used by the compiler to detect errors. Software tools to generate code. They are used to show attributes of an element: e.g. @Deprecated, @Override. Annotation are used to describe the purpose of an element of the framework, e.g. @Entity, @TestCase, @WebService Annotations describe the behaviour of an element: @Statefull, @Transaction. Example class Sample{ public void display(){ System.out.println(" "); } } public class Test extends ...
Read MoreWhat's the simplest way to print a Java array?
Generally, to print the contents of an array you need to use for loops, in addition to that you can directly print an array using the toString() method of this class. This method accepts an array as a parameter and returns it in String format.Exampleimport java.util.Arrays; public class PrintingArrays { public static void main(String args[]) { int[] myArray = {23, 93, 30, 56, 92, 39}; System.out.println(Arrays.toString(myArray)); } }Output[23, 93, 30, 56, 92, 39]
Read MoreJava Program to count letters in a String
Let’s say we have the following string, that has some letters and numbers.String str = "9as78";Now loop through the length of this string and use the Character.isLetter() method. Within that, use the charAt() method to check for each character/ number in the string.for (int i = 0; i < str.length(); i++) { if (Character.isLetter(str.charAt(i))) count++; }We have set a count variable above to get the length of the letters in the string.Here’s the complete example.Examplepublic class Demo { public static void main(String []args) { String str = "9as78"; int count = ...
Read MoreJava Program to convert ASCII code to String
To convert ASCII to string, use the toString() method. Using this method will return the associated character.Let’s say we have the following int value, which works as ASCII for us.int asciiVal = 89;Now, use the toString() method.String str = new Character((char) asciiVal).toString();Examplepublic class Demo { public static void main(String []args) { int asciiVal = 87; String str = new Character((char) asciiVal).toString(); System.out.println(str); } }OutputW
Read MoreSplit String with Comma (,) in Java
Let’s say the following is our string.String str = " This is demo text, and demo line!";To split a string with comma, use the split() method in Java.str.split("[,]", 0);The following is the complete example.Examplepublic class Demo { public static void main(String[] args) { String str = "This is demo text, and demo line!"; String[] res = str.split("[,]", 0); for(String myStr: res) { System.out.println(myStr); } } }OutputThis is demo text and demo line!
Read MoreGet the union of two sets in Java
The union of two sets combines all the unique elements from both sets into one. In Java we can achieve this using the HashSet class, which ensures no duplicate elements. This article will demonstrate two approaches to finding the union of two sets. Different Approaches Following are the two different approaches to getting the union of two sets in Java − Using the addAll() Method Using Streams Using the addAll() Method The simplest way to find the union of two sets is by using the addAll() method of the HashSet class. This ...
Read MoreJava Program to display Frame after some seconds
In this article, we will learn how to display a frame after a few seconds in Java using the Timer class. This example shows how to delay the visibility of a frame by 2 seconds using Swing. Timer() class The Timer class is used to schedule tasks that execute after a specific time interval or repeatedly at regular intervals. It allows tasks to be run by a thread that handles the scheduling and execution. Each task can be set to execute either once or repeatedly at fixed intervals. The execution of all tasks is managed by a background thread associated ...
Read MoreJava program to convert a Map to a read only map
A read-only map in Java is a type of Map that cannot be modified after it has been created. This means that once the map has been set to be read-only, we cannot add, remove, or update any of the key-value pairs.Converting a Map to a read only map We can convert a mutable map to an immutable map, a read-only map using the Collections.unmodifiableMap() method. This method provides a way to make sure that the map cannot be modified once it has been wrapped in this method. Following are the steps to convert a Map to a read-only map ...
Read MoreJava Program to convert from a java.util.Date Object to a java.sql.Date Object
In this article, we will learn to convert a java.util.Date object to a java.sql.Date object in Java. This is a common requirement when working with databases, as many database systems use the java.sql.Date class to represent date values. While java.util.Date is used for general date and time representation in Java, java.sql.Date is specifically designed to handle SQL-compatible date formats. java.util.Date The Date class in the java.util package representing a specific moment in time, measured in milliseconds since January 1, 1970, UTC (the "epoch"). It's a general-purpose date and time representation. java.sql.Date A subclass of ...
Read MoreJava program to add and remove elements from a set which maintains the insertion order
In this article, we will learn how to use a LinkedHashSet in Java to add and remove elements while maintaining the insertion order. You will see how elements are stored, removed, and updated in a LinkedHashSet without altering the sequence in which they were added. Problem Statement Write a Java program to add elements to a LinkedHashSet, remove specific elements, and display the updated set while ensuring the insertion order of the elements remains unchanged. Below is a demonstration of the same − Input Set = [20, 60, 80, 120, 150, 200, 220, 260, 380] Output Set = [20, 60, ...
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