Tech Trek: A Software Engineer's Guide to Code and Beyond

The maven-javadoc plugin can be used to generate a javadoc jar file, It uses JDK's javadoc.exe tools to generate javadocs, p ack in jar file and deploy along with your project. To add support of javadoc in your Maven, Just add 'maven-javadoc' plugin into your pom.xml file and specify goal as 'jar'. Example : <!-- Generates JAVADOC --> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId> maven - javadoc - plugin </artifactId> <executions> <execution> <id>attach- javadocs </id> <goals> <goal>jar</goal> </goals> </execution> </executions> </plugin> Run it as mvn:install or mvn:package, It will generate javadoc and package it as a jar file. Reference: http://maven.apache.org/plugins/maven-javadoc-plugin/      

Java 8 comes up with one great features called Lambda Expressions. It's first step to the functional programming. With Lambda expression we can treat functionality as method arguments i.e. you can pass a method as argument to another method. Previously we use to write anonymous class if we wanted to pass some method as argument to another method but with lambda expression, we can pass a plain method as argument. Lambda expressions is a anonymous function i.e. It has arguments, a body and return type. Syntax of Lambda Expression : (Argument(s)) → {Body} Eg : (int x, int y, int z) - > {return x+y+z}; (String msg) - > {System.out.println(msg);} () - > { return 100;} Structure of Lambda Expression : It can have zero, one or more number of parameters. For empty set of parameters, Empty parentheses are used. e.g () -> 100 Type of the passed parameter can be explicitly declared or can be taken from context. e.g. (int x) is same as (x). One...

The 'javax.imageio.ImageIO' is a handy class which provides lots of utility methods related to images processing in Java. Using this class we can read and write images into disk. In below example, We will see how to use 'javax.imageio.ImageIO' to read an image from URL and save it into different formats. import java.awt.image.BufferedImage; import java.io.File; import java.net.URL; import javax.imageio.ImageIO; /** * This class will download the image from the specified URL and download it in * different format. * * @author abdulwaheed18 @gmail.com * */ public class ImageDownloader { /** * @param args */ public static void main(String[] args ) { String imageUrl = "http://img.gettyimageslatam.com/public/userfiles/redesign/images/landing/home/img_entry_002.jpg" ; try { System. out .println( "Downloading Image..." ); URL url = new URL( imageUrl ); ...

What is Semaphore? Semaphore is used to control access to common resource for completing multiple resources . It guards a critical section against entry by more than N threads at a time. The  java.util.concurrent.Semaphore   class was first introduced by Java in V 1.5. It has two main methods(): ·          acquire() ·          release() Semaphore is initialized with a given number of "permits” i.e. counter which keeps track of the number of resources available. When a request comes to resources, Semaphore checks the counter and if it is less than total count then it grant access to resources and subsequently reduces the counter. Similarly while releasing a resources, it increments the count. Thus, at most N threads can access the acquire method without any release() calls where N is number of permits the semaphore was initialized with. If the permits is in ON|OFF mode i....