Remove StringUtils#join in favor of String#join (Java 8)

src/test/java/fr/xephi/authme/command/CommandInitializerTest.java

@@ -296,17 +296,12 @@ public class CommandInitializerTest {
      * @return List of all bindings that lead to the command
      */
     private static List<String> getAbsoluteLabels(CommandDescription command) {
-        String parentPath = "";
-        CommandDescription elem = command.getParent();
-        while (elem != null) {
-            parentPath = elem.getLabels().get(0) + " " + parentPath;
-            elem = elem.getParent();
-        }
-        parentPath = parentPath.trim();
+        CommandDescription parent = command.getParent();
+        String parentPath = (parent == null) ? "" : parent.getLabels().get(0) + " ";
 
         List<String> bindings = new ArrayList<>(command.getLabels().size());
         for (String label : command.getLabels()) {
-            bindings.add(StringUtils.join(" ", parentPath, label));
+            bindings.add(parentPath + label);
         }
         return bindings;
     }

src/test/java/fr/xephi/authme/command/CommandUtilsTest.java

@@ -3,10 +3,6 @@ package fr.xephi.authme.command;
 import fr.xephi.authme.TestHelper;
 import org.junit.Test;
 
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.junit.Assert.assertThat;
 
@@ -15,42 +11,6 @@ import static org.junit.Assert.assertThat;
  */
 public class CommandUtilsTest {
 
-    @Test
-    public void shouldPrintPartsForStringRepresentation() {
-        // given
-        Iterable<String> parts = Arrays.asList("some", "parts", "for", "test");
-
-        // when
-        String str = CommandUtils.labelsToString(parts);
-
-        // then
-        assertThat(str, equalTo("some parts for test"));
-    }
-
-    @Test
-    public void shouldPrintEmptyStringForNoArguments() {
-        // given
-        List<String> parts = Collections.emptyList();
-
-        // when
-        String str = CommandUtils.labelsToString(parts);
-
-        // then
-        assertThat(str, equalTo(""));
-    }
-
-    @Test
-    public void shouldPrintLabels() {
-        // given
-        List<String> labels = Arrays.asList("authme", "help", "reload");
-
-        // when
-        String result = CommandUtils.labelsToString(labels);
-
-        // then
-        assertThat(result, equalTo("authme help reload"));
-    }
-
     @Test
     public void shouldReturnCommandPath() {
         // given