Java-programs from Hadoop Definitive Guide and online Hadoop tutorials. A note to self is: mkdir weather_classes javac -cp /Users/claus/devel/hadoop/hadoop-core-0.20.203.0.jar -d weather_classes MaxTemperatureMapper.java javac -cp /Users/claus/devel/hadoop/hadoop-core-0.20.203.0.jar -d weather_classes MaxTemperatureReducer.java javac -cp /Users/claus/devel/hadoop/hadoop-core-0.20.203.0.jar:weather_classes -d weather_classes MaxTemperature.java jar -cvf maxtemperature.jar -C weather_classes . hadoop jar maxtemperature.jar no.gnome.mapreduce.MaxTemperature input/temperature output