Copy the first N words in a string in java

I want to select the first N words of a text string. I have tried split() and substring() to no avail. What I want is to select the first 3 words of the following prayer and copy them to another variable.

For example if I have a string:

String greeting = "Hello this is just an example"

I want to get into the variable Z the first 3 words so that

Z = "Hello this is"

    String myString = "Copying first N numbers of words to a string";
    String [] arr = myString.split("\\s+"); 
         //Splits words & assign to the arr[]  ex : arr[0] -> Copying ,arr[1] -> first


        int N=3; // NUMBER OF WORDS THAT YOU NEED
        String nWords="";

        // concatenating number of words that you required
        for(int i=0; i<N ; i++){
             nWords = nWords + " " + arr[i] ;         
        }

    System.out.println(nWords);

NOTE : Here .split() function returns an array of strings computed by splitting a given string around matches of the given regular expression

so if i write the code like follows

String myString = "1234M567M98723651";
String[] arr = myString.split("M"); //idea : split the words if 'M' presents

then answers will be :
1234 and 567 where stored into an array.

This is doing by storing the split values into the given array. first split value store to arr[0], second goes to arr[1].

Later part of the code is for concatenating the required number of split words

Hope that you can get an idea from this!!!
Thank you!