Can someone please help me make my could into 2-3 multiple java files? I really don't know how to break it up and I am afraid if I do, I'll mess it up and have to start all over again. So if any could please help me it would be greatly appreciated.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Vector;


public class HangMan
{
    
    String dictionary[] = { "boy", "girl", "mother", "father", "sister",
        "love", "sky", "wind", "water", "study", "ball", "cat", "dog",
        "puppy", "kitten", "apple", "pear", "lemon", "mango", "peach",
        "apricot", "chips", "steak", "fries", "cheese", "patato", "wedge",
        "heel", "hand", "foot", "arm", "leg", "nose", "face", "mouth",
        "tongue", "fingers", "toes", "line", "space", "phone", "cord",
        "core", "grass", "trees", "birds", "animals", "lazy", "funny",
        "king", "queen", "heart", "heat", "cold", "sun", "moon", "movie",
        "theater", "hairy", "big", "small", "large", "huge", "pig",
        "donkey", "cow", "chicken", "pizza", "bread", "stones", "sticks",
        "leaves", "letters", "alphabet", "soup", "hungry", "tired",
        "sleepy", "noisy", "caring", "friends", "month", "day", "light",
        "toothbrush", "savings", "bank", "account", "teller", "paper",
        "pencil", "tea", "coffee", "spirit", "ghost", "can", "melon",
        "necklace", "screen", "balloon", "string", "calendar", "work",
        "toys", "kids", "school", "class", "campus", "freedom", "liberty",
        "happiness", "university", "message", "marker", "crayon", "eraser",
        "music", "lyrics", "songs", "ballads", "shapes", "triangle",
        "circle", "rectangle", "square", "oval", "show", "video", "player",
        "team", "sport", "basketball", "football", "soccer", "softball",
        "baseball", "tennis", "hockey", "lacrosse", "volleyball", "circuit",
        "blade", "scratch", "hit", "home", "house", "safe", "safety",
        "number", "count", "bear", "goose", "llama", "panda", "lion",
        "tiger", "cheetah", "computer", "crackers", "rice", "fan", "shoes",
        "book", "story", "princess", "prince", "jester", "court", "jury",
        "judge", "bench", "scandal", "name", "newspaper", "press", "shove",
        "tear", "cry", "magic", "tricks", "cereal", "breakfast", "lunch",
        "dinner", "main", "course", "fork", "spoon", "knife", "lamp",
        "desk", "bottle", "highlighter", "cap", "medicine", "six", "seven",
    "flower", "rose", "petal" };
    
    String wordInMemory = null;
    String hang[] = {"(","0","0",")","-","<","=","<"};
    
    public HangMan()
    {
        super();
        
    }
    
    public void startHangman()
    {
        boolean done = false;
        
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
        do
        {
            System.out.print("\t\tEnter your selection:\n\t\t1. Play Hangman \n\t\t2.Exit program\n\t\tChoice = ");
            
            int choice = 0;
            try
            {
                choice = Integer.parseInt(input.readLine());
            }
            catch (NumberFormatException e)
            {
                e.printStackTrace();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            switch (choice)
            {
                case 0:
                {
                    System.out.println("Press 1 or 2");
                    break;
                }
                case 1:
                {
                    play();
                    break;
                }
                case 2:
                {
                    done = true;
                    break;
                }
                default:
                {
                    System.out.println("Press 1 or 2");
                    break;
                }
            }
        }
        while (!done);
    }
    
    private void play()
    {
        int rand_no = (int) (Math.random() * 200);
        if (rand_no > 200)
        {
            rand_no = 200;
        }
        wordInMemory = dictionary[rand_no];
        int numberOfLetters = wordInMemory.length();
        
        //System.out.println("WORD : "+wordInMemory+"\n");
        int falseAttempts = 0;
        int pendingLetters = numberOfLetters;
        boolean won = false;
        String letterGuess = null;
        Vector successAttempt = new Vector();
        Vector wordInVector = new Vector();
        Vector wordTyped = new Vector();
        for(int ini=0;ini<numberOfLetters;ini++)
        {
            successAttempt.addElement(" _ ");
            wordInVector.addElement(""+wordInMemory.charAt(ini));
        }
        System.out.println();
        System.out.print("\t\tWORD : ");
        for(int i=0;i<numberOfLetters;i++)
        {
            System.out.print(successAttempt.elementAt(i));
        }
        
        System.out.println("\n\n");
        
        BufferedReader inBuff = new BufferedReader(new InputStreamReader(System.in));
        do
        {
            System.out.print("\t\tEnter your guess = ");
            try
            {
                letterGuess = inBuff.readLine().toLowerCase();
                if(wordTyped.contains(letterGuess))
                {
                    System.out.println("\t\tYou already guessed this letter early ");
                    continue;
                }
                else
                {
                    wordTyped.addElement(letterGuess);
                    if(wordInMemory.contains(letterGuess))
                    {
                        for(int j=0;j<numberOfLetters;j++)
                        {
                            String letter = (String)wordInVector.elementAt(j);
                            if(letterGuess.equals(letter))
                            {
                                successAttempt.setElementAt(letterGuess,j);
                                pendingLetters--;
                            }
                        }
                        if(pendingLetters == 0)
                        {
                            won = true;
                        }
                        
                    }
                    else
                    {
                        falseAttempts++;
                    }
                }
                System.out.println();
                System.out.print("\t\tWORD : ");
                for(int i=0;i<numberOfLetters;i++)
                {
                    System.out.print(successAttempt.elementAt(i));
                }
                System.out.println();
                System.out.print("\n\t\t");
                for(int f=0;f<falseAttempts;f++)
                {
                    System.out.print(hang[f]);
                }
                System.out.println();
                System.out.print("\n\t\tNo: of Attempts Left : "+(8-falseAttempts));
                System.out.println();
                if(falseAttempts == hang.length)
                {
                    System.out.println("\n\t\t Word is "+wordInMemory);
                }
                System.out.println();
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
        while((falseAttempts < 8) && !won);
        
        if(won)
        {
            System.out.println("\t\tYou guessed it right !");
        }
        else
        {
            System.out.println("\t\tYou lose !");
        }
    }
    
    public static void main(String[] args)
    {
        
        HangMan man = new HangMan();
        man.startHangman();
    }
}

If you back up your work before experimenting you can always revert to a version that worked and start from there...

At the very least get rid of that hardcoded dictionary in your main class, and separate the business logic from the user interface.