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Programming Articles
Page 1513 of 2547
Differentiate between the prefix and postfix forms of the ++ operator in java?
Java provides two operators namely ++ and --, to increment and decrement values by 1 respectively.There are two variants of these operators −Pre-increment/decrement − This form, increments/decrements the value first, and then performs the specified operation.ExampleIn the following example, the initial value of the variable i is 5. We are printing the incremented value of it using the pre increment operator.Since we are using the pre increment operator, the value of i is incremented then printed.public class ForLoopExample { public static void main(String args[]) { int i = 5; System.out.println(++i); ...
Read MoreName validation using Java Regular Expressions
The name can be validated using the java.util.regex.Pattern.matches() method. This method matches the regular expression for the name and the given input name and returns true if they match and false otherwise.A program that demonstrates this is given as follows:Examplepublic class Demo { public static void main(String args[]) { String name = "John Harry Smith"; String regexName = "\p{Upper}(\p{Lower}+\s?)"; String patternName = "(" + regexName + "){2, 3}"; System.out.println("The name is: " + name); System.out.println("Is the above name valid? " + name.matches(patternName)); } ...
Read MoreAlgorithmParameterGenerator getProvider() method in Java
The provider of the generator object can be obtained using the method getProvider() in the class java.security.AlgorithmParameterGenerator. This method requires no parameters and it returns the provider of the generator object.A program that demonstrates this is given as follows −Exampleimport java.security.*; import java.util.*; public class Demo { public static void main(String[] argv) { try { AlgorithmParameterGenerator apGenerator = AlgorithmParameterGenerator.getInstance("DiffieHellman"); apGenerator.init(1024); Provider provider = apGenerator.getProvider(); System.out.println("The Provider is: " + provider); } catch (NoSuchAlgorithmException e) { ...
Read MoreIntStream flatMap() method in Java
The flatMap() method of the IntStream class returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.The syntax is as followsIntStream flatMap(IntFunction
Read MoreCopy all elements of ArrayList to an Object Array in Java
All the elements of an ArrayList can be copied into an Object Array using the method java.util.ArrayList.toArray(). This method does not have any parameters and it returns an Object Array that contains all the elements of the ArrayList copied in the correct order.A program that demonstrates this is given as follows −Exampleimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { List aList = new ArrayList(); aList.add("Nathan"); aList.add("John"); aList.add("Susan"); aList.add("Betty"); aList.add("Peter"); Object[] objArr = ...
Read MoreCan a for statement loop infinitely in java?
Using loops in programming languages we can execute a set of statements repeatedly. Java provides various loops namely while loop, for loop and the do while loop.The for statement contains an initialization statement, a condition and, an increment or decrement operation.Initializing statement − The initialization determines the starting value of the loop.Condition − The condition in for loop is a statement returning a boolean value. This condition determines the exit value of the loop. It is executed before the statements of the loop.Increment and decrement − Using this the loop will be incremented or decremented to the next value.After initializing ...
Read MoreAlgorithmParameterGenerator getAlgorithm() method in Java
The algorithm name for the parameter generator can be obtained using the method getAlgorithm() in the class java.security.AlgorithmParameterGenerator. This method requires no parameters and it returns the algorithm name in string form.A program that demonstrates this is given as follows −Exampleimport java.security.*; import java.util.*; public class Demo { public static void main(String[] argv) { try { AlgorithmParameterGenerator apGenerator = AlgorithmParameterGenerator.getInstance("DiffieHellman"); apGenerator.init(1024); String algorithm = apGenerator.getAlgorithm(); System.out.println("The Algorithm is: " + algorithm); } catch (NoSuchAlgorithmException e) { ...
Read MoreConvert Character Array to IntStream in Java
Let’s say the following is our character array:Character arr[] = { 'V', 'e', 'h', 'i', 'c', 'l' , 'e' };To convert the above character array to IntStreamIntStream stream = Stream.of(arr).flatMapToInt(IntStream::of);We have used the flatMapToInt() method for this.The following is an example to convert character array to IntStream in Java:Exampleimport java.util.stream.*; public class Main { public static void main(String[] args) { Character arr[] = { 'V', 'e', 'h', 'i', 'c', 'l' , 'e' }; System.out.println("The character array = "); for (char value : arr) { System.out.println("Value = ...
Read MoreWhat is deep copy? Explain with an example in Java.
Creating an exact copy of an existing object in the memory is known as cloning.The clone() method of the class java.lang.Object accepts an object as a parameter, creates and returns a copy of it (clones).In order to use this method, you need to make sure that your class implements the Cloneable interface.Exampleimport java.util.Scanner; public class CloneExample implements Cloneable { private String name; private int age; public CloneExample(String name, int age){ this.name = name; this.age = age; } public void displayData(){ System.out.println("Name : "+this.name); ...
Read MoreThe contains() method of CopyOnWriteArrayList in Java
The contains() method of the CopyOnWriteArrayList class is used to get the specified element. It returns TRUE if the element is in the List, else FALSE is returned.The syntax is as followsboolean contains(Object ob)Here, ob is the element to be checked for existence. To work with CopyOnWriteArrayList class, you need to import the following packageimport java.util.concurrent.CopyOnWriteArrayList;The following is an example to implement CopyOnWriteArrayList class contains() method in JavaExampleimport java.util.concurrent.CopyOnWriteArrayList; public class Demo { public static void main(String[] args) { CopyOnWriteArrayList arrList = new CopyOnWriteArrayList(); arrList.add(100); arrList.add(250); arrList.add(400); ...
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