diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/Page.java b/webmagic-core/src/main/java/us/codecraft/webmagic/Page.java
index c11df693c..15206b920 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Page.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Page.java
@@ -49,7 +49,7 @@ public class Page {
 
     private byte[] bytes;
 
-    private List<Request> targetRequests = new ArrayList<Request>();
+    private List<Request> targetRequests = new ArrayList<>();
 
     private String charset;
     
@@ -108,6 +108,7 @@ public Json getJson() {
      * @deprecated since 0.4.0
      * The html is parse just when first time of calling {@link #getHtml()}, so use {@link #setRawText(String)} instead.
      */
+    @Deprecated
     public void setHtml(Html html) {
         this.html = html;
     }
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/Request.java b/webmagic-core/src/main/java/us/codecraft/webmagic/Request.java
index 9fc286192..b73665ab2 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Request.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Request.java
@@ -40,9 +40,9 @@ public class Request implements Serializable {
     /**
      * cookies for current url, if not set use Site's cookies
      */
-    private Map<String, String> cookies = new HashMap<String, String>();
+    private Map<String, String> cookies = new HashMap<>();
 
-    private Map<String, String> headers = new HashMap<String, String>();
+    private Map<String, String> headers = new HashMap<>();
 
     /**
      * Priority of the request.<br>
@@ -94,7 +94,7 @@ public <T> T getExtra(String key) {
 
     public <T> Request putExtra(String key, T value) {
         if (extras == null) {
-            extras = new HashMap<String, Object>();
+            extras = new HashMap<>();
         }
         extras.put(key, value);
         return this;
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/ResultItems.java b/webmagic-core/src/main/java/us/codecraft/webmagic/ResultItems.java
index 488c81e77..273b0a30e 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/ResultItems.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/ResultItems.java
@@ -14,7 +14,7 @@
  */
 public class ResultItems {
 
-    private Map<String, Object> fields = new LinkedHashMap<String, Object>();
+    private Map<String, Object> fields = new LinkedHashMap<>();
 
     private Request request;
 
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/Site.java b/webmagic-core/src/main/java/us/codecraft/webmagic/Site.java
index 4879b2825..9cbda0222 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Site.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Site.java
@@ -22,9 +22,9 @@ public class Site {
 
     private String userAgent;
 
-    private Map<String, String> defaultCookies = new LinkedHashMap<String, String>();
+    private Map<String, String> defaultCookies = new LinkedHashMap<>();
 
-    private Map<String, Map<String, String>> cookies = new HashMap<String, Map<String, String>>();
+    private Map<String, Map<String, String>> cookies = new HashMap<>();
 
     private String charset;
 
@@ -38,11 +38,11 @@ public class Site {
 
     private int timeOut = 5000;
 
-    private static final Set<Integer> DEFAULT_STATUS_CODE_SET = new HashSet<Integer>();
+    private static final Set<Integer> DEFAULT_STATUS_CODE_SET = new HashSet<>();
 
     private Set<Integer> acceptStatCode = DEFAULT_STATUS_CODE_SET;
 
-    private Map<String, String> headers = new HashMap<String, String>();
+    private Map<String, String> headers = new HashMap<>();
 
     private boolean useGzip = true;
 
@@ -83,7 +83,7 @@ public Site addCookie(String name, String value) {
      */
     public Site addCookie(String domain, String name, String value) {
         if (!cookies.containsKey(domain)){
-            cookies.put(domain,new HashMap<String, String>());
+            cookies.put(domain,new HashMap<>());
         }
         cookies.get(domain).put(name, value);
         return this;
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java b/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
index 5940e738d..925548147 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
@@ -62,7 +62,7 @@ public class Spider implements Runnable, Task {
 
     protected Downloader downloader;
 
-    protected List<Pipeline> pipelines = new ArrayList<Pipeline>();
+    protected List<Pipeline> pipelines = new ArrayList<>();
 
     protected PageProcessor pageProcessor;
 
@@ -86,11 +86,11 @@ public class Spider implements Runnable, Task {
 
     protected boolean exitWhenComplete = true;
 
-    protected final static int STAT_INIT = 0;
+    protected static final  int STAT_INIT = 0;
 
-    protected final static int STAT_RUNNING = 1;
+    protected static final int STAT_RUNNING = 1;
 
-    protected final static int STAT_STOPPED = 2;
+    protected static final int STAT_STOPPED = 2;
 
     protected boolean spawnUrl = true;
 
@@ -173,6 +173,7 @@ public Spider setUUID(String uuid) {
      * @param scheduler scheduler
      * @return this
      * @see #setScheduler(us.codecraft.webmagic.scheduler.Scheduler)
+     * @deprecated
      */
     @Deprecated
     public Spider scheduler(Scheduler scheduler) {
@@ -247,7 +248,7 @@ public Spider setPipelines(List<Pipeline> pipelines) {
      * @return this
      */
     public Spider clearPipeline() {
-        pipelines = new ArrayList<Pipeline>();
+        pipelines = new ArrayList<>();
         return this;
     }
 
@@ -438,7 +439,6 @@ private void onDownloadSuccess(Request request, Page page) {
             logger.info("page status code error, page {} , code: {}", request.getUrl(), page.getStatusCode());
         }
         sleep(site.getSleepTime());
-        return;
     }
 
     private void onDownloaderFail(Request request) {
@@ -544,7 +544,7 @@ protected CollectorPipeline getCollectorPipeline() {
     public <T> T get(String url) {
         List<String> urls = WMCollections.newArrayList(url);
         List<T> resultItemses = getAll(urls);
-        if (resultItemses != null && resultItemses.size() > 0) {
+        if (resultItemses != null && !(resultItemses.isEmpty())) {
             return resultItemses.get(0);
         } else {
             return null;
@@ -677,7 +677,7 @@ public Status getStatus() {
 
 
     public enum Status {
-        Init(0), Running(1), Stopped(2);
+        INIT(0), RUNNING(1), STOPPED(2);
 
         private Status(int value) {
             this.value = value;
@@ -696,7 +696,7 @@ public static Status fromValue(int value) {
                 }
             }
             //default value
-            return Init;
+            return INIT;
         }
     }
 
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/AbstractDownloader.java b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/AbstractDownloader.java
index c27292d09..a71a7d876 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/AbstractDownloader.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/AbstractDownloader.java
@@ -32,7 +32,7 @@ public Html download(String url) {
      */
     public Html download(String url, String charset) {
         Page page = download(new Request(url), Site.me().setCharset(charset).toTask());
-        return (Html) page.getHtml();
+        return page.getHtml();
     }
 
     protected void onSuccess(Request request) {
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java
index 49217e111..b2a39e910 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java
@@ -33,7 +33,7 @@ public class HttpClientDownloader extends AbstractDownloader {
 
     private Logger logger = LoggerFactory.getLogger(getClass());
 
-    private final Map<String, CloseableHttpClient> httpClients = new HashMap<String, CloseableHttpClient>();
+    private final Map<String, CloseableHttpClient> httpClients = new HashMap<>();
 
     private HttpClientGenerator httpClientGenerator = new HttpClientGenerator();
 
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/model/HttpRequestBody.java b/webmagic-core/src/main/java/us/codecraft/webmagic/model/HttpRequestBody.java
index 7d3b30785..afd6f88b0 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/model/HttpRequestBody.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/model/HttpRequestBody.java
@@ -16,6 +16,8 @@
  */
 public class HttpRequestBody implements Serializable {
 
+    private static final String ILL_ENC = "illegal encoding ";
+
     private static final long serialVersionUID = 5659170945717023595L;
 
     public static abstract class ContentType {
@@ -68,7 +70,7 @@ public static HttpRequestBody json(String json, String encoding) {
         try {
             return new HttpRequestBody(json.getBytes(encoding), ContentType.JSON, encoding);
         } catch (UnsupportedEncodingException e) {
-            throw new IllegalArgumentException("illegal encoding " + encoding, e);
+            throw new IllegalArgumentException(ILL_ENC + encoding, e);
         }
     }
 
@@ -76,7 +78,7 @@ public static HttpRequestBody xml(String xml, String encoding) {
         try {
             return new HttpRequestBody(xml.getBytes(encoding), ContentType.XML, encoding);
         } catch (UnsupportedEncodingException e) {
-            throw new IllegalArgumentException("illegal encoding " + encoding, e);
+            throw new IllegalArgumentException(ILL_ENC + encoding, e);
         }
     }
 
@@ -92,7 +94,7 @@ public static HttpRequestBody form(Map<String,Object> params, String encoding){
         try {
             return new HttpRequestBody(URLEncodedUtils.format(nameValuePairs, encoding).getBytes(encoding), ContentType.FORM, encoding);
         } catch (UnsupportedEncodingException e) {
-            throw new IllegalArgumentException("illegal encoding " + encoding, e);
+            throw new IllegalArgumentException(ILL_ENC + encoding, e);
         }
     }
 
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/CharsetUtils.java b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/CharsetUtils.java
index ccf00a466..85852bcae 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/CharsetUtils.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/CharsetUtils.java
@@ -19,6 +19,7 @@
  */
 public abstract class CharsetUtils {
 
+    private static final String CHR = "charset";
     private static Logger logger = LoggerFactory.getLogger(CharsetUtils.class);
 
     public static String detectCharset(String contentType, byte[] contentBytes) throws IOException {
@@ -40,9 +41,9 @@ public static String detectCharset(String contentType, byte[] contentBytes) thro
             for (Element link : links) {
                 // 2.1、html4.01 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
                 String metaContent = link.attr("content");
-                String metaCharset = link.attr("charset");
-                if (metaContent.indexOf("charset") != -1) {
-                    metaContent = metaContent.substring(metaContent.indexOf("charset"), metaContent.length());
+                String metaCharset = link.attr(CHR);
+                if (metaContent.indexOf(CHR) != -1) {
+                    metaContent = metaContent.substring(metaContent.indexOf(CHR), metaContent.length());
                     charset = metaContent.split("=")[1];
                     break;
                 }
diff --git a/webmagic-samples/src/main/java/us/codecraft/webmagic/samples/scheduler/ZipCodePageProcessor.java b/webmagic-samples/src/main/java/us/codecraft/webmagic/samples/scheduler/ZipCodePageProcessor.java
index 3f2de70c5..e2759e563 100644
--- a/webmagic-samples/src/main/java/us/codecraft/webmagic/samples/scheduler/ZipCodePageProcessor.java
+++ b/webmagic-samples/src/main/java/us/codecraft/webmagic/samples/scheduler/ZipCodePageProcessor.java
@@ -19,6 +19,7 @@
  */
 public class ZipCodePageProcessor implements PageProcessor {
 
+
     private Site site = Site.me().setCharset("gb2312")
             .setSleepTime(100);
 
diff --git a/webmagic-selenium/src/main/java/us/codecraft/webmagic/downloader/selenium/WebDriverPool.java b/webmagic-selenium/src/main/java/us/codecraft/webmagic/downloader/selenium/WebDriverPool.java
index e1d9dd039..4de3e01ec 100644
--- a/webmagic-selenium/src/main/java/us/codecraft/webmagic/downloader/selenium/WebDriverPool.java
+++ b/webmagic-selenium/src/main/java/us/codecraft/webmagic/downloader/selenium/WebDriverPool.java
@@ -63,6 +63,7 @@ class WebDriverPool {
 	 * @throws IOException
 	 */
 	public void configure() throws IOException {
+		
 		// Read config file
 		sConfig = new Properties();
 		String configFile = DEFAULT_CONFIG_FILE;