Java Code putting values in hashMap -

Java Code putting values in hashMap -

a hashmap stores data.

private final map<videoobj,record> _data = new hashmap<videoobj,record>();

what difference between

record rin= new record(video, numowned+change, numout, numrentals); _data.put(video, rin);

and

record r= _data.get(video); r.numowned+=change;

in cases can create problems values.

video should override equals , hashcode methods , preferably video class should made final.

java hashmap