thread safety bug (#1988)

core/src/main/java/com/taobao/arthas/core/command/monitor200/DashboardCommand.java

@@ -38,6 +38,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Timer;
 import java.util.TimerTask;
+import java.util.concurrent.atomic.AtomicLong;
 
 import static com.taobao.arthas.core.command.model.MemoryEntryVO.TYPE_BUFFER_POOL;
 import static com.taobao.arthas.core.command.model.MemoryEntryVO.TYPE_HEAP;
@@ -66,7 +67,7 @@ public class DashboardCommand extends AnnotatedCommand {
 
     private long interval = 5000;
 
-    private volatile long count = 0;
+    private final AtomicLong count = new AtomicLong(0);
     private volatile Timer timer;
 
     @Option(shortName = "n", longName = "number-of-execution")
@@ -297,7 +298,7 @@ public class DashboardCommand extends AnnotatedCommand {
         @Override
         public void run() {
             try {
-                if (count >= getNumOfExecutions()) {
+                if (count.get() >= getNumOfExecutions()) {
                     // stop the timer
                     timer.cancel();
                     timer.purge();
@@ -329,7 +330,7 @@ public class DashboardCommand extends AnnotatedCommand {
 
                 process.appendResult(dashboardModel);
 
-                count++;
+                count.getAndIncrement();
                 process.times().incrementAndGet();
             } catch (Throwable e) {
                 String msg = "process dashboard failed: " + e.getMessage();

core/src/main/java/com/taobao/arthas/core/shell/command/internal/WordCountHandler.java

@@ -6,6 +6,7 @@ import com.taobao.middleware.cli.CommandLine;
 import com.taobao.middleware.cli.Option;
 
 import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * @author ralf0131 2017-02-23 23:28.
@@ -17,7 +18,7 @@ public class WordCountHandler extends StdoutHandler implements StatisticsFunctio
     private boolean lineMode;
 
     private String result = null;
-    private volatile int total = 0;
+    private final AtomicInteger total = new AtomicInteger(0);
 
     public static StdoutHandler inject(List<CliToken> tokens) {
         List<String> args = StdoutHandler.parseArgs(tokens, NAME);
@@ -39,7 +40,7 @@ public class WordCountHandler extends StdoutHandler implements StatisticsFunctio
             result = "wc currently only support wc -l!\n";
         } else {
             if (input != null && !"".equals(input.trim())) {
-                total += input.split("\n").length;
+                total.getAndAdd(input.split("\n").length);
             }
         }
 
@@ -52,6 +53,6 @@ public class WordCountHandler extends StdoutHandler implements StatisticsFunctio
             return result;
         }
 
-        return total + "\n";
+        return total.get() + "\n";
     }
 }