[attribute][complex] extend to java.util.Map

Add `java.util.Map` to the list of supported `JMXComplexAttribute`
types.

Author: yannmh

src/main/java/org/datadog/jmxfetch/Instance.java

@@ -25,7 +25,7 @@ public class Instance {
             "java.lang.String", "int", "float", "double", "java.lang.Double","java.lang.Float", "java.lang.Integer", "java.lang.Long",
             "java.util.concurrent.atomic.AtomicInteger", "java.util.concurrent.atomic.AtomicLong",
             "java.lang.Object", "java.lang.Boolean", "boolean", "java.lang.Number");
-    private final static List<String> COMPOSED_TYPES = Arrays.asList("javax.management.openmbean.CompositeData", "java.util.HashMap");
+    private final static List<String> COMPOSED_TYPES = Arrays.asList("javax.management.openmbean.CompositeData", "java.util.HashMap", "java.util.Map");
     private final static int MAX_RETURNED_METRICS = 350;
     private final static int DEFAULT_REFRESH_BEANS_PERIOD = 600;
     public static final String PROCESS_NAME_REGEX = "process_name_regex";

src/main/java/org/datadog/jmxfetch/JMXComplexAttribute.java

@@ -34,7 +34,7 @@ private void populateSubAttributeList(Object attributeValue) {
             for (String key : data.getCompositeType().keySet()) {
                 this.subAttributeList.put(key, new HashMap<String, Object>());
             }
-        } else if ("java.util.HashMap".equals(attributeType)) {
+        } else if (("java.util.HashMap".equals(attributeType)) || ("java.util.Map".equals(attributeType))){
             HashMap<String, Double> data = (HashMap<String, Double>) attributeValue;
             for (String key : data.keySet()) {
                 this.subAttributeList.put(key, new HashMap<String, Object>());
@@ -83,7 +83,7 @@ private double getValue(String subAttribute) throws AttributeNotFoundException,
             CompositeData data = (CompositeData) value;
             return getValueAsDouble(data.get(subAttribute));
 
-        } else if ("java.util.HashMap".equals(attributeType)) {
+        } else if (("java.util.HashMap".equals(attributeType)) || ("java.util.Map".equals(attributeType))) {
             HashMap<String, Object> data = (HashMap<String, Object>) value;
             return getValueAsDouble(data.get(subAttribute));
         }