u should be comfortable with java before learning Hadoop technology.
Hadoop having two parts- development plus admin.
hadoop development is based on java. admin require good knowledge od database.
map/reduce, HDFS, Hive, Pig, Mahout, Sqoop are main components of Hadoop.
data analyst require good to have in Pl/Sql, database, application domain specific knowledge, data analysis framework like hadoop etc.
data scientist require good to have in mathematics, statistics, sas etc.
there will be huge demand of big data Hadoop.
Go with Hadoop !!!!
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