HBase shell commands

describe ‘tablename’ : Displays the metadata of particular table Example : describe ’employee’  {NAME => ‘address’, BLOOMFILTER => ‘ROW’, VERSIONS => ‘5’, IN_MEMORY => ‘false’, KEEP_DELETED_CELLS => ‘FALSE’, DATA_BLOCK_ENCODING => ‘NONE’, TTL => ‘FOREVER’, COMPRESSION => ‘GZ’, MIN_VERSIONS => ‘0’, BLOCKCACHE => ‘true’, BLOCKSIZE => ‘65536’, REPLICATION_SCOPE => ‘0’} {NAME => ‘personal_info’, BLOOMFILTER => ‘ROW’, … More HBase shell commands

Asynchronous processing in java

Asynchronous programming is very popular these days, primarily because of its ability to improve the overall throughput on a multi-core system. Asynchronous programming is a programming paradigm that facilitates fast and responsive user interfaces. The asynchronous programming model in Java provides a consistent programming model to write programs that support asynchrony. Asynchronous programming provides a … More Asynchronous processing in java

Python – java integration (Jython continue…)

Friends , Having knowledge of multiple language is good. but sometimes it become cumbersome to use the libraries written in one language into another. Jython provides a way to run python over JVM. Hence allows integration of both java & python. We can use java classes & function in python as well as python libraries … More Python – java integration (Jython continue…)

Front Controller design pattern

The front controller pattern makes sure that there is one and only one point of entry. All requests are investigated, routed to the designated controller and then processed accordingly to the specification. The front controller is responsible of initializing the environment and routing requests to designated controllers. The front controller design pattern is used to … More Front Controller design pattern

Implicit lock vs Exclusive lock in java

On class level, ReentrantLock is a concrete implementation of Lock interface provided in Java concurrency package from Java 1.5 onwards. As per Javadoc, ReentrantLock is mutual exclusive lock, similar to implicit locking provided by synchronized keyword in Java, with extended feature like fairness, which can be used to provide lock to longest waiting thread. Lock … More Implicit lock vs Exclusive lock in java

Reading / Writing in Java

Friends reading & writing operation in java is very easy. To write to a file : File f = new File(“/location/of/file.txt”); if(!f.exists()) { f.createNewFile(); } FileWriter fw = new FileWriter(f,true); //true meaning allow append BufferedWriter wr = new BufferedWriter(fw); wr.write(token); wr.close(); fw.close(); To read file: String data=””; String final_data=””; File f = new File(“/location/of/file.txt”); if (f.exists()) … More Reading / Writing in Java

BoneCP connection pooling – Some useful Tips

Friends , while developing an application which require high availability of application. It is often a requirement to use any kind of connection pooling. BoneCP connection pooling is a database connection pooling which has a good features that i have explained in my earlier post.There are some minor fine tuning require to work with BoneCP. … More BoneCP connection pooling – Some useful Tips