It's doing the thing

src/main/java/io/zipcoder/NumberToWords.java

@@ -0,0 +1,135 @@
+package io.zipcoder;
+
+import java.text.DecimalFormat;
+
+public class NumberToWords {
+
+    private static final String[] tensNames = {
+            "",
+            " Ten",
+            " Twenty",
+            " Thirty",
+            " Forty",
+            " Fifty",
+            " Sixty",
+            " Seventy",
+            " Eighty",
+            " Ninety"
+    };
+
+    private static final String[] numNames = {
+            "",
+            " One",
+            " Two",
+            " Three",
+            " Four",
+            " Five",
+            " Six",
+            " Seven",
+            " Eight",
+            " Nine",
+            " Ten",
+            " Eleven",
+            " Twelve",
+            " Thirteen",
+            " Fourteen",
+            " Fifteen",
+            " Sixteen",
+            " Seventeen",
+            " Eighteen",
+            " Nineteen"
+    };
+
+    public NumberToWords() {}
+
+    private static String convertLessThanOneThousand(int number) {
+        String soFar;
+
+        if (number % 100 < 20){
+            soFar = numNames[number % 100];
+            number /= 100;
+        }
+        else {
+            soFar = numNames[number % 10];
+            number /= 10;
+
+            soFar = tensNames[number % 10] + soFar;
+            number /= 10;
+        }
+        if (number == 0) return soFar;
+        return numNames[number] + " Hundred" + soFar;
+    }
+
+
+    public static String convert(long number) {
+        // 0 to 999 999 999 999
+        if (number == 0) { return "Zero"; }
+
+        String snumber = Long.toString(number);
+
+        // pad with "0"
+        String mask = "000000000000";
+        DecimalFormat df = new DecimalFormat(mask);
+        snumber = df.format(number);
+
+        // XXXnnnnnnnnn
+        int billions = Integer.parseInt(snumber.substring(0,3));
+        // nnnXXXnnnnnn
+        int millions  = Integer.parseInt(snumber.substring(3,6));
+        // nnnnnnXXXnnn
+        int hundredThousands = Integer.parseInt(snumber.substring(6,9));
+        // nnnnnnnnnXXX
+        int thousands = Integer.parseInt(snumber.substring(9,12));
+
+        String tradBillions;
+        switch (billions) {
+            case 0:
+                tradBillions = "";
+                break;
+            case 1 :
+                tradBillions = convertLessThanOneThousand(billions)
+                        + " billion ";
+                break;
+            default :
+                tradBillions = convertLessThanOneThousand(billions)
+                        + " billion ";
+        }
+        String result =  tradBillions;
+
+        String tradMillions;
+        switch (millions) {
+            case 0:
+                tradMillions = "";
+                break;
+            case 1 :
+                tradMillions = convertLessThanOneThousand(millions)
+                        + " million ";
+                break;
+            default :
+                tradMillions = convertLessThanOneThousand(millions)
+                        + " million ";
+        }
+        result =  result + tradMillions;
+
+        String tradHundredThousands;
+        switch (hundredThousands) {
+            case 0:
+                tradHundredThousands = "";
+                break;
+            case 1 :
+                tradHundredThousands = "one thousand ";
+                break;
+            default :
+                tradHundredThousands = convertLessThanOneThousand(hundredThousands)
+                        + " thousand ";
+        }
+        result =  result + tradHundredThousands;
+
+        String tradThousand;
+        tradThousand = convertLessThanOneThousand(thousands);
+        result =  result + tradThousand;
+
+        // remove extra spaces!
+        return result.replaceAll("^\\s+", "").replaceAll("\\b\\s{2,}\\b", " ");
+    }
+}

src/main/java/io/zipcoder/Problem6.java

@@ -1,4 +1,51 @@
 package io.zipcoder;
 
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 public class Problem6 {
+
+    public String militaryTime(String inputTime){
+        String result = "";
+        String regexFormula = "([0-9]*):([0-9]{2})([ap])";
+        Pattern pattern = Pattern.compile(regexFormula);
+        Matcher matcher = pattern.matcher(inputTime);
+        int hour = 0;
+        int minute = 0;
+        String meridiem = "";
+        while (matcher.find()) {
+            hour = Integer.parseInt(matcher.group(1));
+            minute = Integer.parseInt(matcher.group(2));
+            meridiem = matcher.group(3);
+        }
+        if (meridiem.equals("p")){
+            hour += 12;
+        }
+        result += parseHour(hour);
+        result += "Hundred ";
+        result += parseMinute(minute);
+        result += " Hours";
+        return result;
+    }
+
+    private String parseHour(int number){
+        String result = "";
+        if (number < 10){
+            result += "Zero ";
+        }
+        result += NumberToWords.convert(number) + " ";
+        return result;
+    }
+
+    private String parseMinute(int minute){
+        String result = "";
+        if (minute < 10){
+            result += "Zero ";
+        } else {
+            result += "and ";
+        }
+        result += NumberToWords.convert(minute);
+        return result;
+    }
+
 }

src/test/java/io/zipcoder/Problem6Test.java

@@ -1,4 +1,49 @@
 package io.zipcoder;
 
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
 public class Problem6Test {
+    Problem6 problem6;
+
+    @Before
+    public void setup(){
+        problem6 = new Problem6();
+    }
+
+    @Test
+    public void onethirtyTest(){
+        String actual = problem6.militaryTime("1:30am");
+        String expected = "Zero One Hundred and Thirty Hours";
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void oneThirtyPmTest(){
+        String actual = problem6.militaryTime("1:30pm");
+        String expected = "Thirteen Hundred and Thirty Hours";
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void fiveFourtyFivePmTest(){
+        String actual = problem6.militaryTime("5:45pm");
+        String expected = "Seventeen Hundred and Forty Five Hours";
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void tenOhTwoAmTest(){
+        String actual = problem6.militaryTime("10:02am");
+        String expected = "Ten Hundred Zero Two Hours";
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void twoElevenAmTest(){
+        String actual = problem6.militaryTime("2:11am");
+        String expected = "Zero Two Hundred and Eleven Hours";
+        Assert.assertEquals(expected, actual);
+    }
 }