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 886e74a92..9567236b0 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
@@ -458,6 +458,8 @@ protected void sleep(int time) {
             Thread.sleep(time);
         } catch (InterruptedException e) {
             logger.error("Thread interrupted when sleep",e);
+            //restore interrupted thread
+            Thread.currentThread().interrupt();
         }
     }
 
@@ -564,6 +566,7 @@ private void waitNewUrl() {
             newUrlCondition.await(emptySleepTime, TimeUnit.MILLISECONDS);
         } catch (InterruptedException e) {
             logger.warn("waitNewUrl - interrupted, error {}", e);
+            Thread.currentThread().interrupt();
         } finally {
             newUrlLock.unlock();
         }
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/FilePersistentBase.java b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/FilePersistentBase.java
index 79b9efece..721401f8b 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/FilePersistentBase.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/FilePersistentBase.java
@@ -11,6 +11,14 @@
 public class FilePersistentBase {
 
     protected String path;
+    
+    public FilePersistentBase() {
+    	  setPath("/data/webmagic/");
+    }
+    
+    public FilePersistentBase(String path) {
+    	setPath(path);
+    }
 
     public static String PATH_SEPERATOR = "/";
 
diff --git a/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/FilePageModelPipeline.java b/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/FilePageModelPipeline.java
index 0db9b819d..22d818217 100644
--- a/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/FilePageModelPipeline.java
+++ b/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/FilePageModelPipeline.java
@@ -28,11 +28,11 @@ public class FilePageModelPipeline extends FilePersistentBase implements PageMod
      * new JsonFilePageModelPipeline with default path "/data/webmagic/"
      */
     public FilePageModelPipeline() {
-        setPath("/data/webmagic/");
+      super();
     }
 
     public FilePageModelPipeline(String path) {
-        setPath(path);
+        super(path);
     }
 
     @Override
diff --git a/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/JsonFilePageModelPipeline.java b/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/JsonFilePageModelPipeline.java
index 7a7f80a25..7b3b3035c 100644
--- a/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/JsonFilePageModelPipeline.java
+++ b/webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/JsonFilePageModelPipeline.java
@@ -29,11 +29,11 @@ public class JsonFilePageModelPipeline extends FilePersistentBase implements Pag
      * new JsonFilePageModelPipeline with default path "/data/webmagic/"
      */
     public JsonFilePageModelPipeline() {
-        setPath("/data/webmagic/");
+        super();
     }
 
     public JsonFilePageModelPipeline(String path) {
-        setPath(path);
+        super(path);
     }
 
     @Override
diff --git a/webmagic-extension/src/main/java/us/codecraft/webmagic/utils/IPUtils.java b/webmagic-extension/src/main/java/us/codecraft/webmagic/utils/IPUtils.java
index 3d416964b..dafb7ce70 100644
--- a/webmagic-extension/src/main/java/us/codecraft/webmagic/utils/IPUtils.java
+++ b/webmagic-extension/src/main/java/us/codecraft/webmagic/utils/IPUtils.java
@@ -12,7 +12,7 @@
  */
 public abstract class IPUtils {
 
-    public static String getFirstNoLoopbackIPAddresses() throws SocketException {
+    public static String getFirstNoLoopbackIPAddresses() throws SocketException, NullPointerException{
 
         Enumeration<NetworkInterface> networkInterfaces = NetworkInterface.getNetworkInterfaces();