Fixed checkStyle and ErrorProne warns

broker/src/main/java/io/moquette/server/config/ClasspathResourceLoader.java

@@ -19,6 +19,8 @@ package io.moquette.server.config;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
+import java.nio.charset.StandardCharsets;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -51,7 +53,7 @@ public class ClasspathResourceLoader implements IResourceLoader {
     public Reader loadResource(String relativePath) {
         LOG.info("Loading resource. RelativePath = {}.", relativePath);
         InputStream is = this.classLoader.getResourceAsStream(relativePath);
-        return is != null ? new InputStreamReader(is) : null;
+        return is != null ? new InputStreamReader(is, StandardCharsets.UTF_8) : null;
     }
 
     @Override

broker/src/main/java/io/moquette/server/config/ConfigurationParser.java

@@ -24,6 +24,8 @@ import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.Reader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.text.ParseException;
 import java.util.Properties;
 
@@ -55,15 +57,10 @@ class ConfigurationParser {
             return;
         }
         try {
-            FileReader reader = new FileReader(file);
+            Reader reader = Files.newBufferedReader(file.toPath(), StandardCharsets.UTF_8);
             parse(reader);
-        } catch (FileNotFoundException fex) {
-            LOG.warn(
-                    String.format(
-                            "parsing not existing file %s, so fallback on default configuration!",
-                            file.getAbsolutePath()),
-                    fex);
-            return;
+        } catch (IOException fex) {
+            LOG.warn("parsing not existing file {}, fallback on default configuration!", file.getAbsolutePath(), fex);
         }
     }
 

broker/src/main/java/io/moquette/server/config/FileResourceLoader.java

@@ -19,10 +19,15 @@ package io.moquette.server.config;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
+import java.io.IOException;
 import java.io.Reader;
+import java.nio.file.Files;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 public class FileResourceLoader implements IResourceLoader {
 
     private static final Logger LOG = LoggerFactory.getLogger(FileResourceLoader.class);
@@ -68,8 +73,8 @@ public class FileResourceLoader implements IResourceLoader {
             throw new ResourceIsDirectoryException("File \"" + f + "\" is a directory!");
         }
         try {
-            return new FileReader(f);
-        } catch (FileNotFoundException e) {
+            return Files.newBufferedReader(f.toPath(), UTF_8);
+        } catch (IOException e) {
             LOG.error("The file does not exist. Path = {}.", f.getAbsolutePath());
             return null;
         }