FAQ
I have a class to define data I am reading from a MySQL database. According to online tutorials I created a class called MyRecord and extended it from Writable, DBWritable. While running it with hadoop I get a NoSuchMethodException: dataTest$MyRecord.<init>()

I am using 0.21.0

Thanks for your help
Ranjan


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  • John Armstrong at Jul 28, 2011 at 2:48 pm

    On Thu, 28 Jul 2011 10:05:57 -0400, "Kumar, Ranjan" wrote:
    I have a class to define data I am reading from a MySQL database.
    According to online tutorials I created a class called MyRecord and
    extended it from Writable, DBWritable. While running it with hadoop I get a
    NoSuchMethodException: dataTest$MyRecord.<init>()
    Hadoop needs a noargs constructor to build the object, which it then fills
    in by using readFields(). Many classes come with a default noargs
    constructor, which basically defers to the noargs contructor from Object,
    or another ancestor class.

    HOWEVER

    If you defined another constructor that takes arguments, you've implicitly
    removed the default noargs constructor on your class. You need to define
    one explicitly, which Hadoop can use to build your objects.

    hth

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postedJul 28, '11 at 2:42p
activeJul 28, '11 at 2:48p
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