problems with java toLowerCase function when using arrays and multiple 'words' in the string

I am exceptionally new to java, as in, I can barely write 20 lines of basic code and have them work, level of new, I have 2 issues which may or may not be related as they are from very similar pieces of code that I have personally written.

import java.util.Scanner;

public class StringCW {


public static void main (String [] args) {

    String word = ""; 

    while(!(word.equals("stop"))){


        Scanner capconversion = new Scanner(System.in);
        System.out.println("Enter word:" );

        word = capconversion.next(); 
        String lower = word.toLowerCase();
        word = lower;
        System.out.println("conversion = " + word);

    }


    System.out.println("ending program");


        }
    }
}

This is my first chunk of code, it is designed to take any string and convert it into lowercase, however if I am to print anything seperated by a space, eg: "WEWEFRDWSRGdfgdfg DFGDFGDFG" only the first 'word' will be printed and converted, I am also getting a memory leak from cap conversion, though I don't understand what that means or how to fix it

My second problem is likely along the same lines

import java.util.Scanner;

public class splitstring {

private static Scanner capconversion;

public static void main (String [] args) {

    String word = ""; 

    while(!(word.equals("stop"))){

        capconversion = new Scanner(System.in);
        System.out.println("Enter word:" );

        word = capconversion.next(); 
        String lower = word.toLowerCase();
        String[] parts = lower.split(" ");
        parts [0] = "";
        parts [1] = "";
        parts [2] = "";
        parts [3] = "";
        parts [4] = "";


        System.out.println("conversion = " + lower
        parts [0] + parts [1] + parts [2] + parts [3] + parts [4]);

        }

        System.out.println("ending program");
    }
}

this is the 2nd chunk of code and is designed to do the same job as the previous one except print out each 'word' on a new line, then return to the input part until the stop command is entered

the error I get is

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1
    at splitstring.main(splitstring.java:21)

however I don't understand where the error is coming in