I'm using Hadoop version 0.22.0 downloaded [here](http://apache.miloslavbrada.cz/hadoop/common/hadoop-0.22.0/hadoop-0.22.0.tar.gz). I started to create my custom mapper and reducer according to [this](https://ccp.cloudera.com/display/DOC/Hadoop+Tutorial) tutorial and found out that interface `Mapper<K1, V1, K2, V2>` that is to be implemented by all mapper classes is deprecated. Interface `Reducer<K2, V2, K3, V3>` that is meant to be implemented by all reducers (at least according to [the tutorial](https://ccp.cloudera.com/display/DOC/Hadoop+Tutorial)) is also deprecated. So are classes like `MapReduceBase` and `JobConf`. These are all core classes and interfaces that are needed by all custom mappers and reducers, aren't they? There is no note in javadoc what should be used as a replacement of those deprecated classes.

So what interfaces and classes should I use instead of those deprecated ones? Or should I use them anyway? Why are they deprecated? Please just explain to me what's going on and what should I do because I'm not getting it.