It's all about Java

 Write code or write code in right way... Writing a coding solution to a problem can be done in many ways. If the solution can be obtained with less number of code lines, then it is easy to understand and maintain. But what if code is large with having millions of lines. Moreover maintenance and readability becomes difficult as the code base grows... Right?  In this blog I want to share my views and experiences on writing code efficiently and effectively with less maintenance efforts. Aspects to consider while coding: Naming convention Cyclomatic Complexity SOLID principles DRY Principle Managing dead code Comments Naming conventions: Every programming language mandates few norms in order to name variables, classes and functions etc. For ex: Java uses class names first letter to be a alphabet and rest to be lower case letters.  But if we dig little bit more, naming conventions are not limited to only upper case or lower case letters and using alphanumeric letters etc. Nam...

Consider Below points before choosing List concrete implementations for your use case:  ArrayList is a linear data structure and  re-sizable/dynamic array   Initial size can be given. and if not given the default size is 10   It is always good practice to give initial size and advised not to give very large number as size   Good programmers prefer ArrayList to LinkedList if retrieval operations is done more frequently than insertion and deletions of elements.   Better choose LinkedList if insertion and deletion operations are done frequently compared to retrieval operations.   Lists are not sorted. if required use Collections.sort() to sort   Collections.sort() uses optimized merge sort [tim sort] on ArrayList   However legacy merge sort also can be used using a switch. But it is going to be deprecated  in near future  The major difference between ArrayList and LinkedList is RandomAccess behavior...

File Management in OS File management includes files and folders creation, copy and paste operations, reading the file and writing into files and deleting the files and folders  And also reading meta data about files and folders. It may include file free space, occupied space and read/write permissions etc. These above operations are considered as file management and managed by respective operating system. GUI that represents Windows File Manager File Management with Java  Though Java is platform independent, programming language depends on native file IO resources of operating system. This is possible with the Java API support. These API are categorized into 2 types. Readers and Writers: Readers and writers does the IO operations, character by character InputStream and OutputStream: Where as InputStream and OutputStream does IO operations byte by byte Below are simple Java programs that demonstrates different File IO operations. Program for creating directory package com.all...

Software development activities can be managed and taken care with different life cycle models. These life cycle models has became legacy since few years. Few of the available Software Development Life Cycle Models in short SDLC are Win-Win Model and Waterfall Model etc. These traditional models has different phases of development.           1. Requirements            2. Analysis            3. Design            4. Implementation            5. Test           6. Documentation  and 7. Maintenance  In SDLC, the above stages are freezed one after the other. If developer is in Design phase and realized that there could be a possibility of change in requirements, then it is not possible to go back one phase and fix in Requirement phase.  These scenarios and use cases has brough...

Exception: Exception in a programming language and in English language is pretty similar. Exception means being different from or not following the rules. And in programming language like Java, exception is  an event which occurs during the execution of a program that disturbs the complete flow of application or program. When something beyond expected happens while executing a program is considered as an error. handling these errors or abnormality is called as Exception handling. Exception Handling: Exception handling in java is managed with the help of java keywords and java API support..              1. Java Keywords             2. Java API support Java Keywords:   There are 5 keywords in Java.           1. Try           2. catch           3. finally           4. throw    and 5. throws These five keywor...

Java is an object oriented programming language which can be downloaded and installed in your local Machine from java.com To explain java binaries and tools requires block diagram which gives clear picture. For now I brief few important tools. JDK - java development toolkit JVM - Java virtual machine JRE - Java Run time environment From oracle site we can download JDK which is shipped along with JVM and JRM. Mostly java programmers need the JDK. For end users JRE alone is enough. Basic OOPS characteristics are Inheritance Encapsulation Abstraction and Polymorphism The above concepts collectively makes application software extendable and changeable with less effort. Also helps in Developing design patterns. Design patterns gives solutions for common challenges usually a programmer faces while development applications. Factory design pattern, Abstract design pattern, Builder pattern etc. I explain these Design patterns in another article. Inheritance : Inherita...

Immutable objects and mutable objects with an example  In object oriented programming language, in short OOPS, every problem, precisely every requirement is viewed as an object. Understanding the problem in this point of view brings many good things possible in programming like encapsulation, abstraction, polymorphism and inheritance. Anyways this post is not intended for describing benefits of OOPS. Object could be any thing. Let us take Car  for an instance. Basically car is an object and it has name, wheels, metal body, engine, maximum speed,  gear box etc as properties. Let us consider the car name is Ferrari, maximum speed is 200 km per hr with 6 gears. While driving the car driver can change the speed of the car and change the gear etc. So while car is running it's current speed, current gear are considered to be state of the object. The current speed can be changed using accelerator and gear can be changed using gear box. These can be considered as ...

This article is continuation of previous post JFrame usage demo . Please read it before continuing. This post uses the same example code shown in  JFrame usage demo  with JLabel changes and introduces layout manager BorderLayout. Layout Manager: Layout manager is responsible to arrange components on containers. Usually every swing container is created with a default layout manager but can be changed with setLayout() api. For example JFrame uses BorderLayout as default layout amanger. Java program for JLabel 1  2   import java.awt.BorderLayout; 3   import java.awt.Color; 4   import java.awt.Font; 5  6   import javax.swing.JFrame; 7   import javax.swing.JLabel; 8   import javax.swing.SwingUtilities; 9  10  /** 11   * 12   * Simple class to demonstrate JLabel of swing toolkit 13   * 14   * @author Nagasharath 15   * 16  ...

Java Multi threaded programming basics with Reentrant locks As we have seen in earlier post that implicit locking mechanism achieved using synchronized keyword slows down the application performance. Hence java concurrency api gives explicit locking mechanism to achieve mutual exclusion among shared object. How using explicit locks are better than implicit lock? Explicit lock acquires lock per Thread basis and not per method invoke basis. It is inverse in the case of implicit lock.   If a method is synchronized then every invocation of that method involves acquiring and releasing of lock. This process really slows down the application performance.  Hence it is always good idea to prefer reentrent lock or explicit lock to implicit lock. ReentrantLock is a class available in java.util.concurrency package lock() and unlock() methods are used used to acquire and release the lock. Condition class is used in place of Object class wait(), notifyAll() and notify(). ...

Graphical user interface in short GUI makes computer users easy to understand and use the application software comfortably. Almost all modern programming languages allows application developers to develop GUIs. Java has AWT/Swing as default API as part of Java Foundation classes in short JFC which are shipped with JDK. Hence these toolkits can be used directly in our applications with out adding external libraries like jars to our application's class path. But there are some other toolkits which found useful and industry endorsed in developing GUI.      SWT       JFaces [Framework for SWT]      Java FX      Swing      AWT AWT: Abstract window toolkit is available since java first version. AWT uses native operating system resources like Fonts, colors and components like table, tree, dialogues, windows etc. Few notable points about AWT: AWT is heavy weight. It uses OS resources There are l...