Technology blogs for Developers by Developer.

Classes are the building blocks of your java application. If these blocks are not strong, your building (i.e. application) is going to face the tough time in future. This essentially means that not so well-written can lead to very difficult situations when the application scope goes up or application faces certain design issues either in production or maintenance. In this article, I will list down most recommended design principles that you should keep in mind, while writing your classes. These design principles are called SOLID, in short. These principles Make easy for a programmer to develop software that are easy to maintain and extend. They also make it easy for developers to easily refactor code, avoid code smells and are also a part of the agile or adaptive software development. SOLID design principles are : S - Single-responsiblity principle O - Open-closed principle L - Liskov substitution principle I - Interface segregation principle D - Dependency...

Micro web services and Web services are two different concepts of application development architecture, Which can be differentiated from it's development style and layered architecture.In This article I will explain the difference between Web Services and Micro Services Web Services ? Web services are services that are made available from a business's Web server for Web users or other Web-connected programs. it is a way to expose the functionality of an application to other application, without a user interface. It is a service which exposes an API over HTTP. Web Services allow applications developed in different technologies to communicate with each other through a common format like XML, Jason, etc.  Web services are not tied to any one operating system or programming language. For example, an application developed in Java can be used in C#, Android, Php etc., and vice versa.  Web Service is a connection technology, a way to connect services together into a ...

Why Dozer ? Let us think about a situation that you have a source bean which contains lot of fields and the source bean belongs to a different project or module. Now you want to expose the bean to  the outside world as a part of your web service REST service development. It is not advisable to do it. There may be the following reasons. The source bean is not serialized and a final class. The source system does not allow doing it because of security breach. The source bean is very heavy and contains lot of nested beans. The source bean has fields of different types which may not be required for other system. The source bean has lot of fields; some of them are not required. Scenario to use Dozer Suppose You want to make a REST call or web service call to get the minimal account details of a person. But the source system has a bean called “Acc0untBean” which contains many sensitive information like person’s internet banking passw0rd, PAN no or social sec...

Check this article to known about java history. I am sure it will be interesting for you. JDK Version 1.0 First version released on 23 Jan 1996. Code named as OAK. JDK Version 1.1 Released on 19 Feb 1997. Major features are: JDBC (Java Database Connectivity) Inner classes Java beans RMI (Remote Method Invocation) Reflection (introspection only JDK Version 1.2 Releases on 08 Dec 1998. Code named as  Playground. Java String memory map for constants. Collections Framework Just in Time (JIT) Compiler Jar Signer for signing Java Archive (JAR) files. Policy Tool for granting access to system resources. Java Plug-in Audio support in Applets. Scrollable result sets, BLOB, CLOB, batch update, user-defined types in JDBC. Java Foundation Classes (JFC) which consists of Swing 1.0, Drag and Drop, and Java 2D class libraries. JDK Version 1.3 Releases on 08 May 2000. ...

JAVA_OPTS may use by Other applications, but only Tomcat will use CATALINA_OPTS. So if you're setting environment variables for use only by Tomcat, you'll be best advised to use CATALINA_OPTS, whereas if you're setting environment variables to be used by other java applications as well, you should put your settings in JAVA_OPTS. What can go in there! You can increase heap memory available to the JVM. You can open remote monitoring ports so that Jconsole on another system can watch how your Tomcat is running. You can add in a -server to switch from the client (quicker start, slower running) JVM to the server (slower starting, quicker running) JVM. You can increase java thread stack size using the -Xss option (same way to specify amount of memory as in -Xms and -Xmx as described in the "increase heap memory" link above. for more visit : http://www.sanjeevrathaur.com/2015/10/javaopts-variable-details.html

Memory Available to the Java JVM Increasing the memory available to the Java JVM JAVA_OPTS="-Xmx1024m -Xms256m" export JAVA_OPT Options description: -Xmx sets the maximum amount of memory that can be allocated to the JVM heap; here it is being set to 1024 megabytes. -Xms sets the initial amount of memory allocated to the JVM heap; here it is being set to 256 megabytes. Run Java JVM in Server Mode The Java JVM can optimize a number of things for server environments. You can explicitly select the Java HotSpot Server VM with the -server option. JAVA_OPTS="-Xmx1024m -Xms256m -server" export JAVA_OPT What the option means: -server instructs the launcher to use the Java HotSpot Server VM. PermGen Memory If you start getting java.lang.OutOfMemoryError: PermGen space error messages. You may want to include a "-XX:MaxPermSize" option in your JAVA_OPTS. JAVA_OPTS="-Xmx1024m -Xms256m -server -XX:MaxPermSize=128m" export...

Representational State Transfer (REST) has gained widespread acceptance across the Web as a simpler alternative to SOAP- and Web Services Description Language (WSDL)-based Web services. Key evidence of this shift in interface design is the adoption of REST by mainstream Web 2.0 service providers—including Yahoo, Google, and Facebook—who have deprecated or passed on SOAP and WSDL-based interfaces in favour of an easier-to-use, resource-oriented model to expose their services. Basics Fundamental REST didn't attract this much attention when it was first introduced in 2000 by Roy Fielding at the University of California, Irvine, in his academic dissertation, "Architectural Styles and the Design of Network-based Software Architectures," which analyzes a set of software architecture principles that use the Web as a platform for distributed computing. When it's attracting this much attention, a concrete implementation of a REST Web service follows four basic design p...