refractor: fixing word spelling error, fixing some variable 2 lower camel case.

xxl-job-admin/src/main/java/com/xxl/job/admin/core/thread/JobRegistryHelper.java

@@ -134,7 +134,7 @@ public class JobRegistryHelper {
 		// stop registryOrRemoveThreadPool
 		registryOrRemoveThreadPool.shutdownNow();
 
-		// stop monitir (interrupt and wait)
+		// stop monitor (interrupt and wait)
 		registryMonitorThread.interrupt();
 		try {
 			registryMonitorThread.join();

xxl-job-core/src/main/java/com/xxl/job/core/thread/TriggerCallbackThread.java

@@ -240,18 +240,18 @@ public class TriggerCallbackThread {
         }
 
         // load and clear file, retry
-        for (File callbaclLogFile: callbackLogPath.listFiles()) {
-            byte[] callbackParamList_bytes = FileUtil.readFileContent(callbaclLogFile);
+        for (File callbackLogFile: callbackLogPath.listFiles()) {
+            byte[] callbackParamList_bytes = FileUtil.readFileContent(callbackLogFile);
 
             // avoid empty file
             if(callbackParamList_bytes == null || callbackParamList_bytes.length < 1){
-                callbaclLogFile.delete();
+                callbackLogFile.delete();
                 continue;
             }
 
             List<HandleCallbackParam> callbackParamList = (List<HandleCallbackParam>) JdkSerializeTool.deserialize(callbackParamList_bytes, List.class);
 
-            callbaclLogFile.delete();
+            callbackLogFile.delete();
             doCallback(callbackParamList);
         }
 

xxl-job-core/src/main/java/com/xxl/job/core/util/FileUtil.java

@@ -76,16 +76,16 @@ public class FileUtil {
     }
 
     public static byte[] readFileContent(File file) {
-        Long filelength = file.length();
-        byte[] filecontent = new byte[filelength.intValue()];
+        Long fileLength = file.length();
+        byte[] fileContent = new byte[fileLength.intValue()];
 
         FileInputStream in = null;
         try {
             in = new FileInputStream(file);
-            in.read(filecontent);
+            in.read(fileContent);
             in.close();
 
-            return filecontent;
+            return fileContent;
         } catch (Exception e) {
             logger.error(e.getMessage(), e);
             return null;

xxl-job-core/src/main/java/com/xxl/job/core/util/NetUtil.java

@@ -15,7 +15,7 @@ public class NetUtil {
     private static Logger logger = LoggerFactory.getLogger(NetUtil.class);
 
     /**
-     * find avaliable port
+     * find available port
      *
      * @param defaultPort
      * @return