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Java Articles
Page 355 of 450
How to compile packages in Java
Let us look at an example that creates a package called animals. It is a good practice to use names of packages with lower case letters to avoid any conflicts with the names of classes and interfaces.Following package example contains interface named animals −/* File name : Animal.java */ package animals; interface Animal { public void eat(); public void travel(); }Now, let us implement the above interface in the same package animals −package animals; /* File name : MammalInt.java */ public class MammalInt implements Animal { public void eat() { System.out.println("Mammal eats"); } ...
Read MoreDifference between ArrayBlockingQueue and ArrayDeque
ArrayBlockingQueue stores elements in FIFO order. Insertion of element always happened at the tail of the queue and removal of the element always happened from the head of the queue. It is thread safe and It is bounded array queue therefore once created, the capacity cannot be changed. It is the implementation of the Blocking queue.As per Java Docs −Resizable-array implementation of the Deque interface. Array deques have no capacity restrictions; they grow as necessary to support usage. They are not thread-safe; in the absence of external synchronization, they do not support concurrent access by multiple threads. Null elements are ...
Read MoreDifference between OpenId and OAuth
OAuth is designed for providing authorization of the third party without providing password. It is http based. OAuth provides an access token that can be exchanged for any supported assertion via an API.OpenId is designed for authentication. In openId third-party authenticate your users for you, by using accounts they already have. It is used to authenticate single sign-on identitySr. No.KeyOAuthOpenId1BasicOAuth is designed for providing authorization of the third party without providing passwordOpenId is designed for authentication.2SessionIt does not initiate user's session.OpenId initiate user's session3Access TokenIt used token concept to provide authorizationIn openId third-party authenticate your users for you, by using ...
Read MoreHow to Install Rundeck on a Debian 8 (Jessie) Server
Rundeck allows you to run commands/scripts on a remote computer. It is used to create a job by defining a single step or a workflow that can execute any set of commands, scripts, or tools on any number of local or remote nodes. Jobs can be triggered by the scheduler or on-demand via the web interface or API. This article explains about ‘How to install Rundesk on Debian 8 server’Rundeck is written in java programming language, so it requires you to install java in your machine. To install Java programming on Debian, use the following commands –$ sudo dpkg --add-architecture ...
Read MoreHow to Install Java with Apt-Get on Ubuntu 16.04
Java programming language was originally developed by Sun Microsystems which was initiated by James Gosling and released in 1995 as core a component of Sun Microsystems’ Java platform (Java 1.0 [J2SE]).The latest release of the Java Standard Edition is Java SE 8. With the advancement of Java and its widespread popularity, multiple configurations were built to suit various types of platforms. Ex − J2EE for Enterprise Applications, J2ME for Mobile Applications.The new J2 versions was renamed as Java SE, Java EE and Java ME respectively. Java is guaranteed to be a Write Once, Run Anywhere.This article explains about ‘How to ...
Read MoreDifference between Object level lock and Class level lock in Java
In multithreading environment, two or more threads can access the shared resources simultaneously which can lead the inconsistent behavior of the system. Java uses concept of locks to restrict concurrent access of shared resources or objects. Locks can be applied at two levels −Object Level Locks − It can be used when you want non-static method or non-static block of the code should be accessed by only one thread.Class Level locks − It can be used when we want to prevent multiple threads to enter the synchronized block in any of all available instances on runtime. It should always be used ...
Read MoreDifference between Collection.stream().forEach() and Collection.forEach() in Java
Collection.stream().forEach() and Collection.forEach() both are used to iterate over collection. Collection.forEach() uses the collection’s iterator. Most of the collections doesn’t allow the structurally modification while iterating over them. If any element add or remove while iteration they will immediately throw concurrent modification exception. If Collection.forEach() is iterating over the synchronized collection then they will lock the segment of the collection and hold it across all the calls. Collection.stream().forEach() is also used for iterating the collection but it first convert the collection to the stream and then iterate over the stream of the collection therefore the processing order is undefined. It also throws ...
Read MoreXDM – The Download Manager for Linux that ramps up Your Speed to 500%
Xtreme download supervisor (xdman) is an effective download supervisor for Linux, which is developed in Java programing language. It can increase download speeds of upto 500% and is an alternative for the windows IDM (Internet Download Manager). It is compatible with many popular internet browsers such as Firefox, Chrome, Opera.Before installing Xtreme Download supervisor, Check if Java is installed or not available by typing java -version in command line.$ java -versionThe sample output should be like this –openjdk version "1.8.0_91" OpenJDK Runtime Environment (build 1.8.0_91-8u91-b14-0ubuntu4~16.04.1-b14) OpenJDK 64-Bit Server VM (build 25.91-b14, mixed mode)Installing Xtreme Download Manager in LinuxTo put the ...
Read MoreHow to implement DoublePredicate using lambda and method reference in Java?
DoublePredicate is a built-in functional interface defined in java.util.function package. This interface can accept one double-valued parameter as input and produces a boolean value as output. DoublePredicate interface can be used as an assignment target for a lambda expression or method reference. This interface contains one abstract method: test() and three default methods: and(), or() and negate().Syntax@FunctionalInterface public interface DoublePredicate { boolean test(double value) }Example of lambda expressionimport java.util.function.DoublePredicate; public class DoublePredicateLambdaTest { public static void main(String args[]) { DoublePredicate doublePredicate = (double input) -> { // lambda expression if(input == 2.0) { ...
Read MoreHow to match bold fields in a HTML script using a regular expression in Java?
The regular expression "\S" matches a non-whitespace character and the following regular expression matches one or more non space characters between the bold tags."(\S+)"Therefore to match the bold fields in a HTML script you need to −Compile the above regular expression using the compile() method.Retrieve the matcher from the obtained pattern using the matcher() method.Print the matched parts of the input string using the group() method.Exampleimport java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { String str = "This is an example>/b> HTML script."; //Regular expression to match contents of ...
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