Question

I would like to compare a date to the current date. could you please tell me how to do that in java.

Answer 1

Get the dates (however you get them, in the code below it is new Date()) and then use the getTime() to get the Unix time (offset from January 1, 1970, 00:00:00 GMT) to do the comparison

Date then = new Date();
...
Date now = new Date();

long thenInMilliseconds = then.getTime();
long nowInMilliseconds = now.getTime();

if(nowInMilliseconds [<, <=. ==, >=, >] thenInMilliseconds)

You can also use the compareTo method, or as is pointed out in another answer the before and after methods.

EDIT based on comment below:

To parse a date from a String you can use the SimpleDateFormat class (there are other ways too).

For example here is some code I am using for that:

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
Date date = dateFormat.parse("2010-02-12T18:03:15Z");