Caused by: java.lang.NoSuchMethodException: org.apache.hadoop.hdfs.protocol.DatanodeBlocks.()

如果是在hadoop中遇到這個例外
則可能是某個有實作org.apache.hadoop.io.Writable的物件少了沒有引數(argument)的建植子(constructor)

just make sure the class which implements org.apache.hadoop.io.Writable does have a constructor
with no parameters.