/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.text.SimpleDateFormat;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String dt = "1970-12-31";  // Start date
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		Calendar c = Calendar.getInstance();
		c.setTime(sdf.parse(dt));
		c.add(Calendar.DAY_OF_YEAR, 1);  // number of days to add
		dt = sdf.format(c.getTime());  // dt is now the new date
		System.out.println(dt);
	}
}

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