Anagram Tests

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class Anagrams {

    public interface Function {
        public int call() throws Exception;
    }

    public static void main(String[] args) throws Exception {
        if (args.length < 1) {
            System.out.println("Usage: java Anagrams [file]");
            System.exit(1);
        }

        final File file = new File(args[0]);
        int expectedNonAnagram = 65763;

        time("testWithHashMap", 10, new Function() {

            @Override
            public int call() throws IOException {
                return testWithHashMap(file);
            }
        }, expectedNonAnagram);

        time("testWithSorting", 10, new Function() {

            @Override
            public int call() throws IOException {
                return testWithSorting(file);
            }
        }, expectedNonAnagram);

        time("testWithArray", 10, new Function() {

            @Override
            public int call() throws IOException {
                return testWithArray(file);
            }
        }, expectedNonAnagram);

    }

    public static void time(String name, int repetitions, Function function,
            int expectedResult) throws Exception {
        long total = 0;
        for (int i = 0; i < repetitions; i++) {
            System.gc();
            long start = System.currentTimeMillis();
            int result = function.call();
            long end = System.currentTimeMillis();
            if (result != expectedResult) {
                System.out.println("Oops, " + name + " is broken");
                return;
            }
            total += end - start;
        }
        System.out.println("Execution of " + name + " took "
                + (total / repetitions) + " ms on average");
    }

    public static int testWithArray(File file) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(file));
        try {
            String line = reader.readLine();
            int lineNumber = 2;
            int[] firstLineChars = getCharNumberArray(line);
            while ((line = reader.readLine()) != null) {
                int[] currentLineChars = getCharNumberArray(line);
                if (!Arrays.equals(firstLineChars, currentLineChars)) {
                    return lineNumber;
                }
                lineNumber += 1;
            }
        } finally {
            reader.close();
        }
        return -1;
    }

    private static int[] getCharNumberArray(String line) {
        int[] charNumbers = new int[26];
        Arrays.fill(charNumbers, 0);
        for (char c : line.toLowerCase().toCharArray()) {
            if (Character.isAlphabetic(c)) {
                charNumbers[c - 'a'] += 1;
            }
        }
        return charNumbers;
    }

    public static int testWithSorting(File file) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(file));
        try {
            String line = reader.readLine();
            int lineNumber = 2;
            char[] firstLineChars = getSortedChars(line);
            while ((line = reader.readLine()) != null) {
                char[] currentLineChars = getSortedChars(line);
                if (!Arrays.equals(firstLineChars, currentLineChars)) {
                    return lineNumber;
                }
                lineNumber += 1;
            }
        } finally {
            reader.close();
        }
        return -1;
    }

    private static char[] getSortedChars(String line) {
        StringBuilder builder = new StringBuilder();
        for (char c : line.toLowerCase().toCharArray()) {
            if (Character.isAlphabetic(c)) {
                builder.append(c);
            }
        }
        char[] results = builder.toString().toCharArray();
        Arrays.sort(results);
        return results;
    }

    public static int testWithHashMap(File file) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(file));
        try {
            String line = reader.readLine();
            int lineNumber = 2;
            Map<Character, Integer> firstLineCounts = countLetters(line);
            while ((line = reader.readLine()) != null) {
                Map<Character, Integer> currentLineCounts = countLetters(line);
                if (!firstLineCounts.equals(currentLineCounts)) {
                    return lineNumber;
                }
                lineNumber += 1;
            }
        } finally {
            reader.close();
        }
        return -1;
    }

    private static Map<Character, Integer> countLetters(String line) {
        Map<Character, Integer> letterCounts = new HashMap<Character, Integer>();
        for (char c : line.toLowerCase().toCharArray()) {
            if (Character.isAlphabetic(c)) {
                Integer count = letterCounts.get(c);
                if (count == null) {
                    count = 0;
                }
                count += 1;
                letterCounts.put(c, count);
            }
        }
        return letterCounts;
    }
}