Update MRRunningAppMetricBolt.java
Author: yizt
Reviewer: yonzhang

Closes #969
diff --git a/eagle-jpm/eagle-jpm-mr-running/src/main/java/org/apache/eagle/jpm/mr/running/storm/MRRunningAppMetricBolt.java b/eagle-jpm/eagle-jpm-mr-running/src/main/java/org/apache/eagle/jpm/mr/running/storm/MRRunningAppMetricBolt.java
index aa62d30..9cb2510 100644
--- a/eagle-jpm/eagle-jpm-mr-running/src/main/java/org/apache/eagle/jpm/mr/running/storm/MRRunningAppMetricBolt.java
+++ b/eagle-jpm/eagle-jpm-mr-running/src/main/java/org/apache/eagle/jpm/mr/running/storm/MRRunningAppMetricBolt.java
@@ -140,7 +140,7 @@
                 Map<String, String> tags = generateMetricTags(level, app);
                 for (java.util.Map.Entry<String, String> entry : metrics.entrySet()) {
                     Method method = AppInfo.class.getMethod(entry.getValue());
-                    Integer value = (Integer) method.invoke(app);
+                    Integer value = Integer.valueOf(method.invoke(app).toString());
                     String metricName = String.format(entry.getKey(), level.name);
                     createMetric(appMetricEntities, timestamp, tags, metricName, value);
                 }