tl;dr
LocalDate.now( ZoneId.of( "America/Montreal" ) )
.toString()
2016-12-24
Details
The accepted Answer by Cashwell is correct: The formatting pattern codes are incorrect, case-sensitive.
Using java.time
The more modern way to do this is with the java.time classes.
LocalDate
The LocalDate class represents a date-only value without time-of-day and without time zone.
A time zone is crucial in determining a date. For any given moment, the date varies around the globe by zone. For example, a few minutes after midnight in Paris France is a new day while still “yesterday” in Montréal Québec.
ZoneId z = ZoneId.of( "America/Montreal" );
LocalDate today = LocalDate.now( z );
Strings
Your desired output happens to comply with the ISO 8601 standard text formats for date-time values. The java.time classes use ISO 8601 by default when parsing/generating strings. So no need to specify a formatting pattern at all!
String output = today.toString() ;
2016-12-24
By the way, while there is no need to do so in this case, if you were to create a formatting pattern it would look like this code example. The codes are similar to those of SimpleDateFormat but not exactly the same, so study the class doc carefully.
DateTimeFormatter f = DateTimeFormatter.ofPattern( "uuuu-MM-dd" );
String output = today.format( f );
Usually best to also specify a Locale as a habit, but not necessary in this particular case.
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
Where to obtain the java.time classes?
- Java SE 8 and SE 9 and later
- Built-in.
- Part of the standard Java API with a bundled implementation.
- Java 9 adds some minor features and fixes.
- Java SE 6 and SE 7
- Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
- Android
- The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
- See How to use….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.
