how to convert string into date apex code example

Example: format date string in apex

// 2016-02-29
Datetime.now().format('yyyy-MM-dd');

// 2016-02-29T23:50:24Z873
Datetime.now().format('yyyy-MM-dd\'T\'HH:mm:ss\'Z\'SSS');

// 2016.02.29 AD at 23:52:20 EST
Datetime.now().format('yyyy.MM.dd G \'at\' HH:mm:ss z');

// Mon, 29 Feb 2016 23:54:22 -0500
Datetime.now().format('EEE, d MMM yyyy HH:mm:ss Z');

// Today is Monday
Datetime.now().format('\'Today is\' EEEE');

// Tuesday March 01, 2016 is the 61 day of the year
Datetime.now().format('EEEE MMMM dd, YYYY \'is the\' D \'day of the year\'');

// Tuesday March 01, 2016 is the 1 day of the month
Datetime.now().format('EEEE MMMM dd, YYYY \'is the\' d \'day of the month\'');