diff --git a/brut.j.dir/src/main/java/brut/directory/AbstractDirectory.java b/brut.j.dir/src/main/java/brut/directory/AbstractDirectory.java
index 94b63384..68110082 100644
--- a/brut.j.dir/src/main/java/brut/directory/AbstractDirectory.java
+++ b/brut.j.dir/src/main/java/brut/directory/AbstractDirectory.java
@@ -44,7 +44,7 @@ public abstract class AbstractDirectory implements Directory {
             return mFiles;
         }
         if (mFilesRecursive == null) {
-            mFilesRecursive = new LinkedHashSet<String>(mFiles);
+            mFilesRecursive = new LinkedHashSet<>(mFiles);
             for (Map.Entry<String, ? extends Directory> dir : getAbstractDirs().entrySet()) {
                 for (String path : dir.getValue().getFiles(true)) {
                     mFilesRecursive.add(dir.getKey() + separator + path);
@@ -93,7 +93,7 @@ public abstract class AbstractDirectory implements Directory {
     @Override
     public Map<String, Directory> getDirs(boolean recursive)
             throws UnsupportedOperationException {
-        return new LinkedHashMap<String, Directory>(getAbstractDirs(recursive));
+        return new LinkedHashMap<>(getAbstractDirs(recursive));
     }
 
     @Override
@@ -225,7 +225,7 @@ public abstract class AbstractDirectory implements Directory {
             return mDirs;
         }
 
-        Map<String, AbstractDirectory> dirs = new LinkedHashMap<String, AbstractDirectory>(mDirs);
+        Map<String, AbstractDirectory> dirs = new LinkedHashMap<>(mDirs);
         for (Map.Entry<String, AbstractDirectory> dir : getAbstractDirs().entrySet()) {
             for (Map.Entry<String, AbstractDirectory> subdir : dir.getValue().getAbstractDirs(
                     true).entrySet()) {
@@ -260,15 +260,15 @@ public abstract class AbstractDirectory implements Directory {
         return new ParsedPath(path.substring(0, pos), path.substring(pos + 1));        
     }
 
-    abstract protected void loadFiles();
-    abstract protected void loadDirs();
-    abstract protected InputStream getFileInputLocal(String name)
+    protected abstract void loadFiles();
+    protected abstract void loadDirs();
+    protected abstract InputStream getFileInputLocal(String name)
         throws DirectoryException;
-    abstract protected OutputStream getFileOutputLocal(String name)
+    protected abstract OutputStream getFileOutputLocal(String name)
         throws DirectoryException;
-    abstract protected AbstractDirectory createDirLocal(String name)
+    protected abstract AbstractDirectory createDirLocal(String name)
         throws DirectoryException;
-    abstract protected void removeFileLocal(String name);
+    protected abstract void removeFileLocal(String name);
     
     
     private class ParsedPath {
diff --git a/brut.j.dir/src/main/java/brut/directory/DirUtil.java b/brut.j.dir/src/main/java/brut/directory/DirUtil.java
index c7e96e4e..03959e02 100644
--- a/brut.j.dir/src/main/java/brut/directory/DirUtil.java
+++ b/brut.j.dir/src/main/java/brut/directory/DirUtil.java
@@ -28,6 +28,10 @@ import java.util.logging.Logger;
 public class DirUtil {
     private static final Logger LOGGER = Logger.getLogger("");
 
+    private DirUtil() {
+        // Private constructor for utility class
+    }
+    
     public static void copyToDir(Directory in, Directory out)
             throws DirectoryException {
         for (String fileName : in.getFiles(true)) {
diff --git a/brut.j.dir/src/main/java/brut/directory/ZipUtils.java b/brut.j.dir/src/main/java/brut/directory/ZipUtils.java
index 758b0cc7..864af241 100644
--- a/brut.j.dir/src/main/java/brut/directory/ZipUtils.java
+++ b/brut.j.dir/src/main/java/brut/directory/ZipUtils.java
@@ -30,6 +30,10 @@ import java.util.zip.ZipOutputStream;
 public class ZipUtils {
 
     private static Collection<String> mDoNotCompress;
+    
+    private ZipUtils() {
+        // Private constructor for utility class
+    }
 
     public static void zipFolders(final File folder, final File zip, final File assets, final Collection<String> doNotCompress)
             throws BrutException, IOException {
diff --git a/brut.j.util/src/main/java/brut/util/DataInputDelegate.java b/brut.j.util/src/main/java/brut/util/DataInputDelegate.java
index 4b511961..ea579ee7 100644
--- a/brut.j.util/src/main/java/brut/util/DataInputDelegate.java
+++ b/brut.j.util/src/main/java/brut/util/DataInputDelegate.java
@@ -19,7 +19,7 @@ package brut.util;
 import java.io.DataInput;
 import java.io.IOException;
 
-abstract public class DataInputDelegate implements DataInput {
+public abstract class DataInputDelegate implements DataInput {
     protected final DataInput mDelegate;
 
     public DataInputDelegate(DataInput delegate) {
diff --git a/brut.j.util/src/main/java/brut/util/Jar.java b/brut.j.util/src/main/java/brut/util/Jar.java
index b9d2745e..01f4202a 100644
--- a/brut.j.util/src/main/java/brut/util/Jar.java
+++ b/brut.j.util/src/main/java/brut/util/Jar.java
@@ -21,14 +21,11 @@ import org.apache.commons.io.IOUtils;
 
 import java.io.*;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.ThreadLocalRandom;
 
-abstract public class Jar {
-    private final static Set<String> mLoaded = new HashSet<String>();
-    private final static Map<String, File> mExtracted = new HashMap<String, File>();
+public abstract class Jar {
+    private static final Map<String, File> mExtracted = new HashMap<>();
 
     public static File getResourceAsFile(String name, Class clazz) throws BrutException {
         File file = mExtracted.get(name);
diff --git a/brut.j.util/src/main/java/brut/util/OS.java b/brut.j.util/src/main/java/brut/util/OS.java
index e9b8636f..d29aa15e 100644
--- a/brut.j.util/src/main/java/brut/util/OS.java
+++ b/brut.j.util/src/main/java/brut/util/OS.java
@@ -72,11 +72,11 @@ public class OS {
                 continue;
             }
             try {
-                InputStream in = new FileInputStream(file);
-                OutputStream out = new FileOutputStream(destFile);
-                IOUtils.copy(in, out);
-                in.close();
-                out.close();
+                try (InputStream in = new FileInputStream(file)) {
+                    try (OutputStream out = new FileOutputStream(destFile)) {
+                        IOUtils.copy(in, out);
+                    }
+                }
             } catch (IOException ex) {
                 throw new BrutException("Could not copy file: " + file, ex);
             }
@@ -173,7 +173,7 @@ public class OS {
     }
 
     static class StreamCollector implements Runnable {
-        private final StringBuffer buffer = new StringBuffer();
+        private final StringBuilder buffer = new StringBuilder();
         private final InputStream inputStream;
 
         public StreamCollector(InputStream inputStream) {
diff --git a/brut.j.util/src/main/java/brut/util/OSDetection.java b/brut.j.util/src/main/java/brut/util/OSDetection.java
index 749c77d0..58dc5525 100644
--- a/brut.j.util/src/main/java/brut/util/OSDetection.java
+++ b/brut.j.util/src/main/java/brut/util/OSDetection.java
@@ -17,8 +17,8 @@
 package brut.util;
 
 public class OSDetection {
-    private static String OS = System.getProperty("os.name").toLowerCase();
-    private static String Bit = System.getProperty("sun.arch.data.model").toLowerCase();
+    private static final String OS = System.getProperty("os.name").toLowerCase();
+    private static final String BIT = System.getProperty("sun.arch.data.model").toLowerCase();
 
     public static boolean isWindows() {
         return (OS.contains("win"));
@@ -39,7 +39,7 @@ public class OSDetection {
 
             return arch != null && arch.endsWith("64") || wow64Arch != null && wow64Arch.endsWith("64");
         }
-        return Bit.equalsIgnoreCase("64");
+        return BIT.equalsIgnoreCase("64");
     }
 
     public static String returnOS() {