Tutorial by Examples: java

Suppose that we wanted to create a simple Hello World document: In iText 7, we could do that like this: public void createPdf(String dest) throws IOException { PdfDocument pdf = new PdfDocument(new PdfWriter(dest)); Document document = new Document(pdf); document.add(new Paragraph...

When an application has not been packaged as an executable JAR, you need to provide the name of an entry-point class on the java command line. Running the HelloWorld class The "HelloWorld" example is described in Creating a new Java program . It consists of a single class called HelloWo...

This example covers common errors with using the 'java' command. "Command not found" If you get an error message like: java: command not found when trying to run the java command, this means that there is no java command on your shell's command search path. The cause could be: yo...

In Java, activerecord pattern isn't very popular. Though there are some implementations: http://arjava.sourceforge.net/ http://javalite.io/ http://www.javalobby.org/articles/activeobjects/ http://www.jooq.org/

This is a continuation of the "main class" and "executable JAR" examples. Typical Java applications consist of an application-specific code, and various reusable library code that you have implemented or that has been implemented by third parties. The latter are commonly referr...

The fork/join framework in Java is ideal for a problem that can be divided into smaller pieces and solved in parallel. The fundamental steps of a fork/join problem are: Divide the problem into multiple pieces Solve each of the pieces in parallel to each other Combine each of the sub-solutions ...

The Maven Surefire plugin runs during the test phase of the Maven build process or when test is specified as a Maven goal. The following directory structure and minimum pom.xml file will configure Maven to run a test. Directory structure inside the project's root directory: ─ project_root ├─ p...

Modal dialog components can be instantiated via jQuery with the function $('#myModal').modal(options), where $('#myModal') is a top-level reference to the specific modal dialog and options is a Javascript object specifying the modal dialog's default attributes. The options object allows for multipl...

Real life use cases for Singleton pattern; If you are developing a client-server application, you need single instrance of ConnectionManager, which manages the life cycle of client connections. The basic APIs in ConnectionManager : registerConnection: Add new connection to existing list of connec...

function bubbleSort(a) { var swapped; do { swapped = false; for (var i=0; i < a.length-1; i++) { if (a[i] > a[i+1]) { var temp = a[i]; ...

Scala offers implicit conversions between all the major collection types in the JavaConverters object. The following type conversions are bidirectional. Scala TypeJava TypeIteratorjava.util.IteratorIteratorjava.util.EnumerationIteratorjava.util.IterableIteratorjava.util.Collectionmutable.Bufferjav...

NativeScript's global timer variable lets you set timeouts and intervals for asynchronous delayed function calls. Importing var timer = require("timer") Timeouts var callback = function(){ console.log("I will be executed once after 500ms"); } var timeoutId = timer.se...

In PubNub JavaScript v3, you could implement a unique callback for every channel that you subscribed to as long as you called the subscribe function for each channel and implemented the callback in that subscribe like this: var pubnub = new PubNub({ publishKey: "your-pub-key", s...

Here's how to Handle a popup alert in Java with Selenium: There are 3 types of popups. Simple alert : alert("This is a simple alert"); Confirmation alert : var popuResult = confirm("Confirm pop up with OK and Cancel button"); Prompt alert : var person = prompt(&...

using CLI: $ opennlp SentenceDetector ./en-sent.bin < ./input.txt > output.txt using API: import static java.nio.file.Files.readAllBytes; import static java.nio.file.Paths.get; import java.io.IOException; import java.util.Objects; public class FileUtils { /** * Get file data as...

Install the required dependencies: 'org.apache.solr:solr-solrj:5.5.1' 'org.apache.httpcomponents:httpclient:4.3.6' 'com.ibm.watson.developer_cloud:java-sdk:3.2.0' The code below assumes you have a Solr collection with documents and you have trained a ranker, otherwise follow this tutorial pub...

OpenCv image read from file system in Java import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.imgcodecs.Imgcodecs; public class Giris { public static void main(String[] args) { //Load native library System.loadLibrary(Core.NATIVE_LIBRARY_NAME...

Mediator pattern defines an object (Mediator) that encapsulates how a set of objects interact. It enables many-to-many communication. UML diagram: Key components: Mediator: Defines an interface for communication between Colleagues. Colleague: Is an abstract class, which defines the events to b...

Helpers and fakeApplication Class Helpers is used a lot for unit tests. It imitates a Play application, fakes HTTP requests and responses, session, cookies - all whatever may be needed for tests. A controller under the test should be executed in a context of a Play application. The Helpers method f...

You can get easily get this information by barfing out the input in your handler function. For example, in Java: public String handleRequest(String input, Context context) { context.getLogger().log("Input: " + input); String output = "Input:" + System.getProperty(&qu...