Is it Possible to Return Two ArrayList values in One method in java?

No you can not return two value from a method.

Best way would be create a custom class with two field and return that object.

class ObjectHolder{
    private List<Date> startDate=new ArrayList<Date>();
    private List<Date> endDate=new ArrayList<Date>();

    <getter & setter method>
}

and -

public ObjectHolder returnTwoArrayList(){
    ObjectHolder oh = new ObjectHolder();
    List<Date> startDate=new ArrayList<Date>();
    oh.setStartDate(startDate);
    List<Date> endDate=new ArrayList<Date>();
    oh.setEndDate(endDate);
    return oh;
}

You can

• provide one or both lists as argument(s) to populate.
• have two lists which are fields of the instance of the method and access these via getters.
• return an array of two lists or a list of lists.
• return a custom type which wrap the two lists. I wouldn't use getters, just makes the fields public.
• have a single list of intervals

I believe the last is the best solution.

public class Sample {
  public List<Interval> returnListOfStartToEndDates() {
      List<Interval> intervals=new ArrayList<>();

      return intervals;
   }
}

Joda-time has an Interval class which is more efficient than creating two Date objects, but you can also create your own.

You could create a custom class like this

TimeSpan(ArrayList<Date> startDate, ArrayList<Date> endDate)

and return that Object.

Directly, no, unless you count returning an array of two Lists, or a List of Lists with the stated understanding to the caller that it would contain exactly two entries and what value each one would represent.

Other than that, you could always write a Pair class and use that, which would be better because it removes the dependence on that assumption about the dimension of the return value, and you will find that a Pair type comes in handy in many, many situations.

Instead you can use Map like the following,

public Map<String, List<Date>> getBothDates() {
  List<Date> startDate = new ArrayList<Date>();
  List<Date> endDate = new ArrayList<Date>();
  Map<String, List<Date>> bothDates = new HashMap<String, List<Date>>();
  bothDates.put("startDate", startDate);
  bothDates.put("endDate", endDate);    
  return bothDates;
}

To fetch both dates simple iterate the map,

public void printBothDates() {
   Map<String, List<Date>> bothDates = getBothDates();
   for(Entry<String, List<Date>> entry : bothDates.entrySet()) {
     if(StringUtils.equalsIgnoreCase("startDate", entry.getKey())) {
       for(Date d : entry.getValue()) {
          System.out.println("startDate---"+d);
       }
     } else if(StringUtils.equalsIgnoreCase("endDate", entry.getKey())) {
       for(Date d : entry.getValue()) {
          System.out.println("endDate---"+d);
       }
     }
   }
}

import java.util.ArrayList;

public class MyClass {
    public ArrayList<ArrayList> TwoArrayList() {

        ArrayList cars = new ArrayList();
        cars.add("Volvo");
        cars.add("BMW");
        cars.add("Ford");
        cars.add("Mazda");

        ArrayList fruits = new ArrayList();
        fruits.add("Apple");
        fruits.add("Mango");
        fruits.add("Banana");
        fruits.add("Orange");

        ArrayList <ArrayList> twoArrayList = new ArrayList <ArrayList>();
        twoArrayList.add(cars);
        twoArrayList.add(fruits);

        return twoArrayList;

    }

    public static void main(String[] args) {
       MyClass obj = new MyClass();

        ArrayList <ArrayList> Arlist= obj.TwoArrayList();
        
        System.out.println(Arlist.get(0));/**FIRST ARRAY LIST*/
        
        System.out.println(Arlist.get(0).get(0));/**FIRST ARRAY LIST FIRST Element*/

        System.out.println(Arlist.get(1));/**SECOND ARRAY LIST*/
        
        System.out.println(Arlist.get(1).get(0));/**SECOND ARRAY LIST FIRST Element*/
    }  
}  

OUTPUT IS HERE

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