An example of converting multiple lines to single array split on space chars.

ExampleMultipleStringsToList.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class ExampleMultipleStringsToList {

	public static void main(String[] args) {
		  // read in a line
        Scanner scanner = new Scanner(System.in);
    
        System.out.print("Enter a sentence : ");
        String s1 = scanner.nextLine();

        System.out.print("Enter a second sentence : ");
        String s2 = scanner.nextLine();

        System.out.print("Enter a third sentence : ");
        String s3 = scanner.nextLine();
        
        String combined = s1 + " " + s2 + " " + s3;
        String [] words = combined.split(" ");
        
        
        List<String> aList = new ArrayList<>();

        aList.addAll(Arrays.asList(words));
        
        System.out.println(aList);
        
	}
}