THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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First of all, you need the Hadoop source code. The official location for Hadoop is the Apache Git repository. See GitAndHadoop Git And Hadoop
Read BUILDING.txt
Once you have the source code, we strongly recommend reading BUILDING.txt located in the root of the source tree. It has up to date information on how to build Hadoop on various platforms along with some workarounds for platform-specific quirks. The latest BUILDING.txt for the current trunk can also be viewed on the web.
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