AWS, BIG DATA, JAVA

Dynamic Web Project Make sure the files listed under are under webContent folder. When you publish the content to any embeded server, it only publishes content from webContent folder. So any resource under the top level project folder, but not under webContent folder will not be published to the server. If you are using web.xml web-app descriptor 2.5, then use Tomcat 6.x/ java ee 1.6 combination because Tomcat 5.x/java ee 1.5 combination may not work with it. This is what I have seen. Running Unit Tests inside Eclipse At times I have seen different results based on how you run the unit test. This may simply be the configuration issue. So If I am in the unit test class , right mouse click and do Run As =>Junit  Test, it runs fine. If I select the file from left navigation inside Package Explorer and click Run from top  "Run" menu, I see the result is different and at times tests fail.  Now If go and run the same test using maven command line, it is most stric...

NoSQL Data Stores MongoDB ( C++) - document database CouchDB - document database(key/value ) Cassandra - Column based , no single point of failure(Dynamo Architecture), Data modeling is based on Google Big Table. Hbase ( Java )  - Google BigTable based architecture, Column Oriented distributed database on top of HDFS ( non distributed version works on local filesystem also , but distributed is only supported on HDFS).  See  cassandra-vs-hbase  for differences between Cassandra vs. Hbase.  High availability(No single point of failure-almost 100% uptime) , high number of reads/writes and if read/write consistency is not big issue Cassandra is wins. If Read/Write consistency is important and also if you need to query(read) large amount of data and extract small amount of result out of it Hbase wins.  Cassandra includes data storage and management both while Hbase is only for data management. For most of other activities, it relies on external services l...