[ONOS-4938] Defect fix: range interval

Change-Id: I3229d35fb7c80da3bcf150d52ed7e7eba72bb4c8
diff --git a/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/utils/builtindatatype/YangUint64.java b/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/utils/builtindatatype/YangUint64.java
index 49a5153..16576c9 100644
--- a/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/utils/builtindatatype/YangUint64.java
+++ b/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/utils/builtindatatype/YangUint64.java
@@ -18,7 +18,6 @@
 
 import java.io.Serializable;
 import java.math.BigInteger;
-import java.util.regex.Pattern;
 
 /**
  * Handles the YANG's Uint16 data type processing.
@@ -40,11 +39,6 @@
     private static final String MAX_KEYWORD = "max";
 
     /**
-     * YANG's Integer value pattern.
-     */
-    private static final Pattern NON_NEGATIVE_INTEGER_PATTERN = Pattern.compile("[0-9]+");
-
-    /**
      * Valid minimum value of YANG's Uint64.
      */
     public static final BigInteger MIN_VALUE = BigInteger.valueOf(0);
@@ -71,11 +65,13 @@
             value = MIN_VALUE;
         } else if (valueInString.matches(MAX_KEYWORD)) {
             value = MAX_VALUE;
-        } else if (NON_NEGATIVE_INTEGER_PATTERN.matcher(valueInString).matches()) {
-            value = new BigInteger(valueInString);
         } else {
-            throw new DataTypeException("YANG file error : Input value \"" + valueInString + "\" is not a valid " +
-                    "uint64.");
+            try {
+                value = new BigInteger(valueInString);
+            } catch (Exception e) {
+                throw new DataTypeException("YANG file error : Input value \"" + valueInString + "\" is not a valid " +
+                                                    "uint64.");
+            }
         }
 
         if (value.compareTo(MIN_VALUE) < 0) {