What Is Writable & Writablecomparable Interface?

1.	What Is Writable & Writablecomparable Interface?
Answer» org.apache.hadoop.io.Writable is a Java interface. Any key or value TYPE in the Hadoop Map-Reduce framework implements this interface. IMPLEMENTATIONS typically IMPLEMENT a static read(DataInput) method which constructs a new instance, calls readFields(DataInput) and returns the instance. org.apache.hadoop.io.WritableComparable is a Java interface. Any type which is to be used as a key in the Hadoop Map-Reduce framework should implement this interface. WritableComparable objects can be compared to each other USING COMPARATORS.

Answer»

org.apache.hadoop.io.Writable is a Java interface. Any key or value TYPE in the Hadoop Map-Reduce framework implements this interface. IMPLEMENTATIONS typically IMPLEMENT a static read(DataInput) method which constructs a new instance, calls readFields(DataInput) and returns the instance.
org.apache.hadoop.io.WritableComparable is a Java interface. Any type which is to be used as a key in the Hadoop Map-Reduce framework should implement this interface. WritableComparable objects can be compared to each other USING COMPARATORS.

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