Can any one tel me any 5 features used in java?

Question

features insense lik we use scanner for input lik tat is thr anyothr clas used to get input?lik tat som different features...example lik math.pi

Answer 1

i cant understand correctly.does it mean Most used classes in Java?
For files we use File class.
for get dates we use Date class;
for get stream from any url,string file.. we use Input stream
for write something we use OutputStream
for do some mathemtical problems we use Math class.
...

Answer 2

yes...tel me som classes lik tat...i need to use 5 classes lik tat in my program...tel me some rare ones...i mean noned d regular ones lik math class date class calender class...tel me somthng else pls.