Programming Articles - Page 1432 of 3366

The String class of the java.lang package represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class. Strings are constant, their values cannot be changed after they are created.The valueOf() method of the String class accepts a char or, char array or, double or, float or, int or, long or an object as a parameter and returns its String representation.ExampleLive Demoimport java.util.Scanner; public class ConversionOfDouble {    public static void main(String args[]) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter a double value:");       ... Read More

The append method of the StringBuilder or StringBuffer objects accept a boolean or, char or, char array or, double or, float or, int or, long or, String value as parameter and adds it to the current object.You can append the required double value to the method and retrieve a String from obtained StringBuffer (or, StringBuilder) objects.ExampleLive Demoimport java.util.Scanner; public class ConversionOfDouble {    public static void main(String args[]) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter a double value:");       double d = sc.nextDouble();       StringBuffer sb = new StringBuffer();       sb.append(d); ... Read More

Enumerations in Java represents a group of named constants, you can create an enumeration using the following syntax −enum Days {    SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }You can retrieve the contents of an enum using the values() method. This method returns an array containing all the values. Once you obtain the array you can iterate it using the for loop.Examplepublic class IterateEnum{    public static void main(String args[]) {       Days days[] = Days.values();       System.out.println("Contents of the enum are: ");             //Iterating enum using the for loop ... Read More

Enumerations in Java represents a group of named constants, you can create an enumeration using the following syntax −enum Days {    SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }We can an enumeration inside a class. But, we cannot define an enum inside a method. If you try to do so it generates a compile time error saying “enum types must not be local”.Examplepublic class EnumExample{    public void sample() {       enum Vehicles {          Activa125, Activa5G, Access125, Vespa, TVSJupiter;       }    } }ErrorEnumExample.java:3: error: enum types must not be local ... Read More

Enumerations in Java represents a group of named constants, you can create an enumeration using the following syntaxenum Days {    SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }Yes, we can define an enumeration inside a class. You can retrieve the values in an enumeration using the values() method.ExampleLive Demopublic class EnumerationExample {    enum Enum {       Mango, Banana, Orange, Grapes, Thursday, Apple    }    public static void main(String args[]) {       Enum constants[] = Enum.values();       System.out.println("Value of constants: ");         for(Enum d: constants) {         ... Read More

Following example prints the files in a directory based on the extensions −Exampleimport java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.util.stream.Stream; public class Demo {    public static void main(String[] args) throws IOException {       Stream path = Files.walk(Paths.get("D:\ExampleDirectory"));       System.out.println("List of PDF files:");       path = path.filter(var -> var.toString().endsWith(".pdf"));       path.forEach(System.out::println);             path = Files.walk(Paths.get("D:\ExampleDirectory"));       System.out.println("List of JPG files:");       path = path.filter(var -> var.toString().endsWith(".jpg"));       path.forEach(System.out::println);           path = Files.walk(Paths.get("D:\ExampleDirectory"));       ... Read More

The ListFiles() method returns an array holding the objects (abstract paths) of all the files (and directories) in the path represented by the current (File) object.The File Filter interface is filter for the path names you can pass this as a parameter to the listFiles() method. This method filters the file names passed on the passed filter.To get the hidden directories in a folder, implement a FileFilter which accepts only hidden directories, and pass it as a parameter to the listFiles() method.Exampleimport java.io.File; import java.io.FileFilter; import java.io.IOException; public class Test{    public static void main(String args[]) throws IOException {   ... Read More

While you use the methods that causes IllegalArgumentException, since you know the legal arguments of them, you can restrict/validate the arguments using if-condition before-hand and avoid the exception.We can restrict the argument value of a method using the if statement. For example, if a method accepts values of certain range, you can verify the range of the argument using the if statement before executing the method.ExampleFollowing example handles the IllegalArgumentException caused by the setPriority() method using the if statement.Live Demoimport java.util.Scanner; public class IllegalArgumentExample {    public static void main(String args[]) {       Thread thread = new Thread(); ... Read More

The ListFiles() method returns an array holding the objects (abstract paths) of all the files (and directories) in the path represented by the current (File) object.The File Filter interface is filter for the path names you can pass this as a parameter to the listFiles() method. This method filters the file names passed on the passed filter.To get the directories in a folder implement a FileFilter which accepts only empty directories, and pass it as a parameter to the listFiles() method.Exampleimport java.io.File; import java.io.FileFilter; import java.io.IOException; public class MyExample{    public static void main(String args[]) throws IOException {     ... Read More

Array is a container which can hold a fix number of items and these items should be of the same type. Most of the data structures make use of arrays to implement their algorithms. Following are the important terms to understand the concept of Array.Element: Each item stored in an array is called an element.Index: Each location of an element in an array has a numerical index, which is used to identify the element.Creating object arraysYes, since objects are also considered as datatypes (reference) in Java, you can create an array of the type of a particular class and, populate ... Read More