How to pass multiple array lists as a parameter in a method in java?

Question

How do I also pass the arraylist 'end' as a parameter inside the begin method along with the 'start' arraylist?

List<String> start = new ArrayList<String>();
List<String> end = new ArrayList<String>(); 

public static void begin(List<String> start)
{

}

Answer 1

While multiple parameters is definitely the recommended way to do it, there are a few alternative non-recommended ways to achieve this as well. Enjoy!

import java.util.List;

public class ParameterListTest {

  public static void main(String[] args) {
    List<String> startList = List.of("Value1", "Value2");
    List<String> endList = List.of("Value3", "Value4"); 
    
    //Recommended way
    version1(startList, endList);
    
    //Goofy alternatives
    version2(startList, endList);
    
    List<String>[] listArray = new List[]{startList, endList};
    version3(listArray);
    
    List<List<String>> nestedList = List.of(startList, endList);
    version4(nestedList);
  }
  
  public static void version1(List<String> start, List<String> end) {
    System.out.println("Version 1");
    System.out.println(start);
    System.out.println(end);
    System.out.println();
  }
  
  public static void version2(List<String>...lists) {
    System.out.println("Version 2");
    System.out.println(lists[0]);
    System.out.println(lists[1]);
    System.out.println();
  }
  
  public static void version3(List<String>[] lists) {
    System.out.println("Version 3");
    System.out.println(lists[0]);
    System.out.println(lists[1]);
    System.out.println();
  }
  
  public static void version4(List<List<String>> nest) {
    System.out.println("Version 4");
    System.out.println(nest.get(0));
    System.out.println(nest.get(1));
    System.out.println();
  }
}