Fixed suggested.

Test ordering fixed.
Example uses StringBuilders
Example uses one loop encode method
added braces to one-line if statements
etc.

exercises/run-length-encoding/build.gradle

@@ -1,17 +1,17 @@
-apply plugin: "java"
-apply plugin: "eclipse"
-apply plugin: "idea"
-
-repositories {
-    mavenCentral()
-}
-
-dependencies {
-    testCompile "junit:junit:4.12"
-}
-test {
-    testLogging {
-        exceptionFormat = 'full'
-        events = ["passed", "failed", "skipped"]
-    }
-}
+apply plugin: "java"
+apply plugin: "eclipse"
+apply plugin: "idea"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testCompile "junit:junit:4.12"
+}
+test {
+    testLogging {
+        exceptionFormat = 'full'
+        events = ["passed", "failed", "skipped"]
+    }
+}

exercises/run-length-encoding/src/example/java/RunLengthEncoding.java

@@ -1,47 +1,65 @@
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-public class RunLengthEncoding {
-    public String encode(String data) {
-        String encodedData = "";
-
-        for (int i = 0; i < data.length(); i++) {
-            char c = data.charAt(i);
-
-            if (i != 0 && c == data.charAt(i - 1)) continue;
-
-            int amt = 1;
-
-            for (int j = i + 1; j < data.length() && c == data.charAt(j); j++) {
-                amt++;
-            }
-
-            if (amt == 1) encodedData += c;
-            else encodedData += amt + Character.toString(c);
-        }
-
-        return encodedData;
-    }
-
-    public String decode(String encodedData) {
-        String decodedData = "";
-        Pattern pattern = Pattern.compile("[0-9]+|[a-zA-Z\\s]");
-        Matcher matcher = pattern.matcher(encodedData);
-
-        while (matcher.find()) {
-            try {
-                int number = Integer.parseInt(matcher.group());
-
-                matcher.find();
-
-                while (number-- != 0) {
-                    decodedData += matcher.group();
-                }
-            } catch (NumberFormatException e) {
-                decodedData += matcher.group();
-            }
-        }
-
-        return decodedData;
-    }
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class RunLengthEncoding {
+    public String encode(String data) {
+
+        StringBuilder encodedData = new StringBuilder();
+
+        if (data.length() == 0) {
+            return data;
+        }
+
+        int charCount = 0;
+        char beforeChar = data.charAt(0);
+
+        for (int i = 0; i < data.length(); i++) {
+            char currentChar = data.charAt(i);
+
+            if (beforeChar == currentChar) {
+                charCount++;
+
+                if (i != data.length() - 1) {
+                    continue;
+                }
+            }
+
+            if (charCount != 1) {
+                encodedData.append(charCount);
+            }
+
+            encodedData.append(beforeChar);
+
+            if (beforeChar != currentChar && i == data.length() - 1) {
+                encodedData.append(currentChar);
+            }
+
+            beforeChar = currentChar;
+            charCount = 1;
+        }
+
+        return encodedData.toString();
+    }
+
+    public String decode(String encodedData) {
+        StringBuilder decodedData = new StringBuilder();
+        Pattern pattern = Pattern.compile("[0-9]+|[a-zA-Z\\s]");
+        Matcher matcher = pattern.matcher(encodedData);
+
+        while (matcher.find()) {
+            try {
+                int number = Integer.parseInt(matcher.group());
+
+                matcher.find();
+
+                for (; number != 0; --number) {
+                    decodedData.append(matcher.group());
+                }
+            } catch (NumberFormatException e) {
+                decodedData.append(matcher.group());
+            }
+        }
+
+        return decodedData.toString();
+    }
 }

exercises/run-length-encoding/src/main/java/RunLengthEncoding.java

@@ -1,9 +1,12 @@
-public class RunLengthEncoding {
-    public String encode(String input) {
-        throw new UnsupportedOperationException("Method has not been implemented yet.");
-    }
-
-    public String decode(String input) {
-        throw new UnsupportedOperationException("Method has not been implemented yet.");
-    }
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class RunLengthEncoding {
+    public String encode(String data) {
+        throw new UnsupportedOperationException("Method has not been implemented yet.");
+    }
+
+    public String decode(String encodedData) {
+        throw new UnsupportedOperationException("Method has not been implemented yet.");
+    }
 }

exercises/run-length-encoding/src/test/java/RunLengthEncodingTest.java

@@ -1,79 +1,92 @@
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.Ignore;
-import org.junit.Test;
-
-public class RunLengthEncodingTest {
-    private RunLengthEncoding runLengthEncoding;
-
-    @Before
-    public void setUp() {
-        runLengthEncoding = new RunLengthEncoding();
-    }
-
-    @Test
-    public void encodeEmpty() {
-        Assert.assertEquals("", runLengthEncoding.encode(""));
-    }
-
-    @Test
-    public void decodeEmpty() {
-        Assert.assertEquals("", runLengthEncoding.decode(""));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void encodeWithOnlySingleValues() {
-        Assert.assertEquals("XYZ", runLengthEncoding.encode("XYZ"));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void decodeWithOnlySingleValues() {
-        Assert.assertEquals("XYZ", runLengthEncoding.decode("XYZ"));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void encodeWithMixedValues() {
-        Assert.assertEquals("12WB12W3B24WB", runLengthEncoding.encode("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB"));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void decodeWithMixedValues() {
-        Assert.assertEquals("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB", runLengthEncoding.decode("12WB12W3B24WB"));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void encodeWithWhitespaceValues() {
-        Assert.assertEquals("2 hs2q q2w2 ", runLengthEncoding.encode("  hsqq qww  "));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void decodeWithWhitespaceValues() {
-        Assert.assertEquals("  hsqq qww  ", runLengthEncoding.decode("2 hs2q q2w2 "));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void encodeWithLowercaseValues() {
-        Assert.assertEquals("2a3b4c", runLengthEncoding.encode("aabbbcccc"));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void decodeWithLowercaseValues() {
-        Assert.assertEquals("aabbbcccc", runLengthEncoding.decode("2a3b4c"));
-    }
-
-    @Ignore("Remove to run test")
-    @Test
-    public void encodeThenDecode() {
-        String inOut = "zzz ZZ  zZ";
-        String encoded = runLengthEncoding.encode(inOut);
-        Assert.assertEquals(inOut, runLengthEncoding.decode(encoded));
-    }
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class RunLengthEncodingTest {
+    private RunLengthEncoding runLengthEncoding;
+
+    @Before
+    public void setUp() {
+        runLengthEncoding = new RunLengthEncoding();
+    }
+
+    @Test
+    public void encodeEmpty() {
+        Assert.assertEquals("", runLengthEncoding.encode(""));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void encodeWithOnlySingleValues() {
+        Assert.assertEquals("XYZ", runLengthEncoding.encode("XYZ"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void encodeWithNoSingleValues() {
+        Assert.assertEquals("2A3B4C", runLengthEncoding.encode("AABBBCCCC"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void encodeWithMixedValues() {
+        Assert.assertEquals("12WB12W3B24WB", runLengthEncoding.encode("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void encodeWithWhitespaceValues() {
+        Assert.assertEquals("2 hs2q q2w2 ", runLengthEncoding.encode("  hsqq qww  "));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void encodeWithLowercaseValues() {
+        Assert.assertEquals("2a3b4c", runLengthEncoding.encode("aabbbcccc"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void decodeEmpty() {
+        Assert.assertEquals("", runLengthEncoding.decode(""));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void decodeWithOnlySingleValues() {
+        Assert.assertEquals("XYZ", runLengthEncoding.decode("XYZ"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void decodeWithNoSingleValues() {
+        Assert.assertEquals("AABBBCCCC", runLengthEncoding.decode("2A3B4C"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void decodeWithMixedValues() {
+        Assert.assertEquals("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB", runLengthEncoding.decode("12WB12W3B24WB"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void decodeWithWhitespaceValues() {
+        Assert.assertEquals("  hsqq qww  ", runLengthEncoding.decode("2 hs2q q2w2 "));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void decodeWithLowercaseValues() {
+        Assert.assertEquals("aabbbcccc", runLengthEncoding.decode("2a3b4c"));
+    }
+
+    @Ignore("Remove to run test")
+    @Test
+    public void encodeThenDecode() {
+        String inOut = "zzz ZZ  zZ";
+        String encoded = runLengthEncoding.encode(inOut);
+        Assert.assertEquals(inOut, runLengthEncoding.decode(encoded));
+    }
 }