java string to date , date to string

import java.text.SimpleDateFormat;
import java.util.Date;		
		
        //String to Date
        String str="2020-08-12 17:52:08";		
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		Date strToDate=sdf.parse(str);	//return : Wed Aug 12 17:52:08 KST 2020		
        
        //Date to String
        SimpleDateFormat f1 = new SimpleDateFormat("yyyyMMdd");	
		SimpleDateFormat f2 = new SimpleDateFormat("yyyy-MM-dd");
		SimpleDateFormat f3 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		
		Date sysdate =  new Date();	//return : Wed Aug 12 17:52:08 KST 2020
        
		String sys1=f1.format(sysdate);
		String sys2=f2.format(sysdate);
		String sys3=f3.format(sysdate);
        
		System.out.println(sys1);	//return : 20200812
		System.out.println(sys2);	//return : 2020-08-12
		System.out.println(sys3);	//return : 2020-08-12 17:52:08