Consuming Web Services in CXF: Non-blocking / Asynchronous Invocation Model
I’m just gonna reproduce what’s available here – http://cxf.apache.org/docs/developing-a-consumer.html – with additional comments to help you understand how you can asynchronously consume web services using CXF. Along with the usual synchronous mode of invocation, CXF also supports two forms of asynchronous invocation as of writing this: Polling approach - in this case, to invoke the remote [...]
Maven Repository Concepts: Releases vs Snapshots repository
A Maven remote repository can further be segregated as Release / Snapshot repositories. Release / Snapshot repos are always remote, since the local repository has effectively no concept of differentiation between releases and snapshots. Also note that remote repositories can be set to release both snapshots and releases simultaneously. Release Release repositories are designed to [...]
Marshalling / Unmarshalling Java Objects: Serialization vs Externalization
We all know the Java platform allows us to create reusable objects in memory. However, all of those objects exist only as long as the Java virtual machine remains running. It would be nice if the objects we create could exist beyond the lifetime of the virtual machine. Well, with object serialization, you can flatten [...]
A case study on why / how eBay uses of open source WSO2 ESB to process over 1 billion transactions per day
Here’s a case study by WSO2 on eBay‘s use of their open source product in Enterprise Service Bus space – WSO2 ESB. The case study describes in brief the ESB selection process, WSO2′s architectural approach / deployment. WSO2 manages mediation and orchestration within the eBay service-oriented architecture (SOA). Currently the WSO2 ESB instances handle all [...]
Avoiding Full Table Scan / Sequential Scan in MySQL
Full Table Scan / Sequential Scan Quoting from Wikipedia, “Full table scan is a scan made on the database where each row of the table under scan is read in a sequential (serial) order and the columns encountered are checked for the validity of a condition. Full table scans are usually the slowest method of [...]
Java HotSpot VM (Virtual Machine) Performance Tuning: Command-line options
Performance Options Option and Default Value Description -XX:+AggressiveOpts Turn on point performance compiler optimizations that are expected to be default in upcoming releases. (Introduced in 5.0 update 6.) -XX:CompileThreshold=10000 Number of method invocations/branches before compiling [-client: 1,500] -XX:LargePageSizeInBytes=4m Sets the large page size used for the Java heap. (Introduced in 1.4.0 update 1.) [amd64: 2m.] [...]
Datatype Conversion in Java: XMLGregorianCalendar to java.util.Date / java.util.Date to XMLGregorianCalendar
Why do we need XMLGregorianCalendar? Java Architecture for XML Binding (JAXB) allows Java developers to map Java classes to XML representations. JAXB provides two main features: the ability to marshal Java objects into XML and the inverse, i.e. to unmarshal XML back into Java objects. In the default data type bindings i.e. mappings of XML Schema [...]
Getting started with OpenStack, an open source cloud computing platform – A general and technical overview
What is OpenStack? OpenStack is a collection of open source software projects that enterprises/service providers can use to setup and run their cloud compute and storage infrastructure. Rackspace and NASA are the key initial contributors to the stack. Rackspace contributed their “Cloud Files” platform (code) to power the Object Storage part of the OpenStack, while [...]
SQLs to select / retrieve a random row for different RDBMSes – Oracle, MySQL, IBM DB2, PostgreSQL, Microsoft SQL Server, etc.
Sometime, you might get a requirement to display record(s) in UI randomly – say, randomly displaying other pages of the blog at the end of a particular article. Here’s the SQL you need for this purpose for the most common RDBMSes out there: i) Oracle ii) MySQL iii) IBM DB2 iv) PostgreSQL v) Microsoft SQL [...]
Getting started with NoSQL: NoSQL vs RDBMS, Types of NoSQL databases, SWOT analysis, and Dark side of NoSQL
What is NoSQL, how is it different from RDBMS? In computing, NoSQL (sometimes expanded to “not only SQL”) is a broad class of database management systems that differ from the classic model of the relational database management system (RDBMS) in some significant ways, most important being they do not use SQL as their query language. [...]
