What is the use of "lenient "?

Question

Here lenient is used in Java DateFormat. I checked the doc, but didn't get what it was saying.

Can any body please tell me what is the use of this lenient, with one real time example where we use it?

Answer 1

The javadoc clearly states:

Specify whether or not date/time parsing is to be lenient. With lenient parsing, the parser may use heuristics to interpret inputs that do not precisely match this object's format. With strict parsing, inputs must match this object's format.

So, if you have a pattern and create a date object that strictly matches your pattern, set lenient to false. Also, DateFormat is lenient, by default.

Basically, DateFormat sets Calendar.setLenient and the Javadoc states:

Specifies whether or not date/time interpretation is to be lenient. With lenient interpretation, a date such as "February 942, 1996" will be treated as being equivalent to the 941st day after February 1, 1996. With strict (non-lenient) interpretation, such dates will cause an exception to be thrown. The default is lenient.

Answer 2

For example this:

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy"); System.out.println(simpleDateFormat.parse("0")); simpleDateFormat.setLenient(false); System.out.println(simpleDateFormat.parse("0")); 

results in:

Thu Jan 01 00:00:00 CET 1 Exception in thread "main" java.text.ParseException: Unparseable date: "0"     at java.text.DateFormat.parse(Unknown Source)     at net.java.quickcheck.generator.support.X.main(X.java:28)