Hi Arun,

http://cloudera.com/content/cloudera/en/training/certification/ccdh/prep.html

1) Which is the latest cloudera developer certification as of November 2014 and what version of CDH we need to learn?

 - this is largely immaterial for a developer. The changes in 5 are largely resource mgmt (administrator) specific. As the exam is a role-based exam and not a product exam, the versions are somewhat fluid and immaterial.

2) How much java is required to take the test?..For Example Basic Core Java skill or Advanced java like (Generics,Reflection,Threading) or knowledge of J2EE

- You should know how to read and write Java MapReduce code. There are no Java questions outside the context of MapReduce. No Java EE and nothing advanced in the Java sense. 

3) I know to develop hive,pig,Map Reduce codes based on Apache packages/api..Does Cloudera's package differs much from apache's?

- Cloudera ships the open source packages. There is zero difference.

4) what  components from hadoop ecosystem should be learnt for  hadoop developer certification?

- http://cloudera.com/content/cloudera/en/training/certification/ccdh/prep.html

5) Does knowledge of Data Science / Hadoop Administration required for hadoop developer certification?

- No data science; you need to understand the architecture of a cluster but not how to install, tune, secure, etc. that cluster. you need to know how to submit jobs, etc...some of which people would think of a devops.