java interface example

why we should extend interface...anyway we are not going to not use the methods and fields from one interface into other interface..then why does interface extend other interface..if necessary the class can implement the particular interface..

just nw i've started learning java..pls sorry,if the ques is funny..but pls give the ans....

i think sometimes while you are design your software model you face a cases when you has one general interface that is used in many sub models which in behalf have interfaces extends that general interface.