public class Utils {

/**

* Returns a copy of the array 'in' where each word occurring in the array

* 'what' has been replaced by the word occurring in the same position

* in the array 'with'.

*

* @param in an array of Strings;

* @param what an array of words to be replaced;

* @param with an array of replacement words;

* @return a new array idententical to 'in' except that all the occurrences of words

* found in 'what' have been replaced by the corresponding word from 'with'.

*/

public static String[] findAndReplace( String[] in, String[] what, String[] with ) {

String[] out = null; // The new array to be returned

boolean valid = true; // True if the pre-conditions are satistified

// Testing pre-conditions

if ( in == null || what == null || with == null ) {

valid = false;

} else {

// more or less 16 lines missing

}

if ( valid ) {

out = new String[ in.length ];

for ( int i=0; i

//more or less 10 lines missing

}

}

// Returning a reference to the newly created array that

// contains the same entries as 'in' except that all the

// occurrences of words from 'what' have been replaced by

// their corresponding occurrence from 'with'.

return out;

}

}

Done in Java, please add comments for understanding. Thanks!

2 Manipulating arrays - FindAndReplace Complete the implementation of the (static) class method String[] findAndReplace(String[] in, String[] what, String[] with) of the class Utils. The method returns a copy of the array in where each word occurring in the array what has been replaced by the word occurring at the corresponding position in the array with. The array designated by in must remain unchanged. If there are duplicate words in the array what, simply use the first instance you find. Later in the semester, we will learn about exceptions. Exceptions provide tools for handling error situations. In the meantime, the method findAndReplace returns null whenever one of the preconditions of the methods is violated: In particular, the formal parameters cannot be null. For all three arrays, none of the elements can be null. The query and replacement arrays must be of the same length. You will hand this exercise in. Download and complete the starter file here: Utils.java