Fix some minor issues discovered by PMD plugins

dubbo-common/src/main/java/org/apache/dubbo/common/io/Bytes.java

@@ -19,10 +19,10 @@
 import org.apache.dubbo.common.utils.IOUtils;
 
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.file.Files;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Map;
@@ -844,7 +844,7 @@ public static byte[] getMD5(byte[] source) {
      * @return MD5 byte array.
      */
     public static byte[] getMD5(File file) throws IOException {
-        InputStream is = new FileInputStream(file);
+        InputStream is = Files.newInputStream(file.toPath());
         try {
             return getMD5(is);
         } finally {

dubbo-common/src/main/java/org/apache/dubbo/common/utils/AnnotationUtils.java

@@ -154,7 +154,7 @@ static <T> T getAttribute(Annotation annotation, String... attributeNames) throw
             }
 
             //  exclude string attribute  default is empty
-            if ((attribute instanceof String) && ((String) attribute).length() == 0) {
+            if ((attribute instanceof String) && ((String) attribute).isEmpty()) {
                 continue;
             }
 

dubbo-common/src/main/java/org/apache/dubbo/common/utils/CompatibleTypeUtils.java

@@ -80,13 +80,13 @@ public static Object compatibleTypeConvert(Object value, Class<?> type) {
                 return new BigDecimal(string);
             }
             if (type == Short.class || type == short.class) {
-                return new Short(string);
+                return Short.valueOf(string);
             }
             if (type == Integer.class || type == int.class) {
-                return new Integer(string);
+                return Integer.valueOf(string);
             }
             if (type == Long.class || type == long.class) {
-                return new Long(string);
+                return Long.valueOf(string);
             }
             if (type == Double.class || type == double.class) {
                 return new Double(string);
@@ -95,7 +95,7 @@ public static Object compatibleTypeConvert(Object value, Class<?> type) {
                 return new Float(string);
             }
             if (type == Byte.class || type == byte.class) {
-                return new Byte(string);
+                return Byte.valueOf(string);
             }
             if (type == Boolean.class || type == boolean.class) {
                 return Boolean.valueOf(string);

dubbo-common/src/main/java/org/apache/dubbo/common/utils/IOUtils.java

@@ -21,7 +21,6 @@
 import java.io.BufferedReader;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -36,6 +35,7 @@
 import java.io.Writer;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -168,7 +168,7 @@ public static String[] readLines(File file) throws IOException {
             return new String[0];
         }
 
-        return readLines(new FileInputStream(file));
+        return readLines(Files.newInputStream(file.toPath()));
     }
 
     /**
@@ -228,7 +228,7 @@ public static void writeLines(File file, String[] lines) throws IOException {
         if (file == null) {
             throw new IOException("File is null.");
         }
-        writeLines(new FileOutputStream(file), lines);
+        writeLines(Files.newOutputStream(file.toPath()), lines);
     }
 
     /**

dubbo-common/src/main/java/org/apache/dubbo/config/ReferenceConfigBase.java

@@ -321,7 +321,7 @@ protected void resolveFile() {
                     resolveFile = userResolveFile.getAbsolutePath();
                 }
             }
-            if (resolveFile != null && resolveFile.length() > 0) {
+            if (resolveFile != null && !resolveFile.isEmpty()) {
                 Properties properties = new RegexProperties();
                 try (FileInputStream fis = new FileInputStream(resolveFile)) {
                     properties.load(fis);

dubbo-compatible/src/main/java/com/alibaba/dubbo/container/page/ResourceFilter.java

@@ -27,11 +27,12 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -50,10 +51,10 @@ public class ResourceFilter implements Filter {
 
     public void init(FilterConfig filterConfig) throws ServletException {
         String config = filterConfig.getInitParameter("resources");
-        if (config != null && config.length() > 0) {
+        if (config != null && !config.isEmpty()) {
             String[] configs = Constants.COMMA_SPLIT_PATTERN.split(config);
             for (String c : configs) {
-                if (c != null && c.length() > 0) {
+                if (c != null && !c.isEmpty()) {
                     c = c.replace('\\', '/');
                     if (c.endsWith("/")) {
                         c = c.substring(0, c.length() - 1);
@@ -118,7 +119,7 @@ private boolean isFile(String path) {
 
     private long getLastModified(String uri) {
         for (String resource : resources) {
-            if (resource != null && resource.length() > 0) {
+            if (resource != null && !resource.isEmpty()) {
                 String path = resource + uri;
                 if (isFile(path)) {
                     File file = new File(path);
@@ -136,7 +137,7 @@ private InputStream getInputStream(String uri) {
             String path = resource + uri;
             try {
                 if (isFile(path)) {
-                    return new FileInputStream(path);
+                    return Files.newInputStream(Paths.get(path));
                 } else if (path.startsWith(CLASSPATH_PREFIX)) {
                     return Thread.currentThread()
                             .getContextClassLoader()

dubbo-metadata/dubbo-metadata-api/src/main/java/org/apache/dubbo/metadata/report/support/AbstractMetadataReport.java

@@ -36,13 +36,13 @@
 import org.apache.dubbo.rpc.model.ApplicationModel;
 
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.RandomAccessFile;
 import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.Iterator;
@@ -233,7 +233,7 @@ private void doSaveProperties(long version) {
 
     void loadProperties() {
         if (file != null && file.exists()) {
-            try (InputStream in = new FileInputStream(file)) {
+            try (InputStream in = Files.newInputStream(file.toPath())) {
                 properties.load(in);
                 if (logger.isInfoEnabled()) {
                     logger.info("Load service store file " + file + ", data: " + properties);

dubbo-rpc/dubbo-rpc-api/src/main/java/org/apache/dubbo/rpc/support/RpcUtils.java

@@ -110,7 +110,7 @@ public static Type[] getReturnTypes(Invocation invocation) {
 
     public static Long getInvocationId(Invocation inv) {
         String id = inv.getAttachment(ID_KEY);
-        return id == null ? null : new Long(id);
+        return id == null ? null : Long.valueOf(id);
     }
 
     /**

dubbo-test/dubbo-test-check/src/main/java/org/apache/dubbo/test/check/registrycenter/initializer/UnpackZookeeperInitializer.java

@@ -32,7 +32,7 @@
 import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
 import org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream;
-import org.apache.commons.compress.utils.IOUtils;
+import org.apache.commons.io.IOUtils;
 
 /**
  * Unpack the downloaded zookeeper binary archive.
@@ -52,7 +52,7 @@ private void unpack(ZookeeperContext context, int clientPort) throws DubboTestEx
         File sourceFile = context.getSourceFile().toFile();
         Path targetPath = Paths.get(context.getSourceFile().getParent().toString(), String.valueOf(clientPort));
         // check if it's unpacked.
-        if (targetPath.toFile() != null && targetPath.toFile().isDirectory()) {
+        if (targetPath.toFile().isDirectory()) {
             logger.info(String.format("The file has been unpacked, target path:%s", targetPath.toString()));
             return;
         }
@@ -87,28 +87,31 @@ protected void doInitialize(ZookeeperContext context) throws DubboTestException
             // get the file name, just like apache-zookeeper-{version}-bin
             // the version we maybe unknown if the zookeeper archive binary file is copied by user self.
             Path parentPath = Paths.get(context.getSourceFile().getParent().toString(), String.valueOf(clientPort));
-            if (!Files.exists(parentPath)
-                    || !parentPath.toFile().isDirectory()
-                    || parentPath.toFile().listFiles().length != 1) {
+            if (!Files.exists(parentPath) || !parentPath.toFile().isDirectory()) {
+                throw new IllegalStateException("There is something wrong in unpacked file!");
+            }
+
+            File[] files = parentPath.toFile().listFiles();
+            if (files == null || files.length != 1) {
                 throw new IllegalStateException("There is something wrong in unpacked file!");
             }
             // rename directory
-            File sourceFile = parentPath.toFile().listFiles()[0];
-            File targetFile = Paths.get(parentPath.toString(), context.getUnpackedDirectory())
-                    .toFile();
+            File sourceFile = files[0];
+            File targetFile = Paths.get(parentPath.toString(), context.getUnpackedDirectory()).toFile();
             sourceFile.renameTo(targetFile);
             if (!Files.exists(targetFile.toPath()) || !targetFile.isDirectory()) {
-                throw new IllegalStateException(String.format(
-                        "Failed to rename the directory. source directory: %s, target directory: %s",
-                        sourceFile.toPath().toString(), targetFile.toPath().toString()));
+                throw new IllegalStateException(String.format("Failed to rename the directory. source directory: %s, target directory: %s", sourceFile.toPath(), targetFile.toPath()));
             }
             // get the bin path
             Path zookeeperBin = Paths.get(targetFile.toString(), "bin");
             // update file permission
-            for (File file : zookeeperBin.toFile().listFiles()) {
-                file.setExecutable(true, false);
-                file.setReadable(true, false);
-                file.setWritable(false, false);
+            File[] zookeeperBinFiles = zookeeperBin.toFile().listFiles();
+            if (zookeeperBinFiles != null) {
+                for (File file : zookeeperBinFiles) {
+                    file.setExecutable(true, false);
+                    file.setReadable(true, false);
+                    file.setWritable(false, false);
+                }
             }
         }
     }