diff --git a/python/dllib/src/bigdl/dllib/utils/file_utils.py b/python/dllib/src/bigdl/dllib/utils/file_utils.py
index 0e1fa58c3d0..f0f8b484e63 100644
--- a/python/dllib/src/bigdl/dllib/utils/file_utils.py
+++ b/python/dllib/src/bigdl/dllib/utils/file_utils.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-from bigdl.util.common import Sample as BSample, JTensor as BJTensor, callBigDlFunc
+from bigdl.util.common import Sample as BSample, JTensor as BJTensor,\
+    JavaCreator, _get_gateway, _java2py, _py2java
 import numpy as np
 
 
 def to_list_of_numpy(elements):
-
     if isinstance(elements, np.ndarray):
         return [elements]
     elif np.isscalar(elements):
@@ -39,7 +39,28 @@ def to_list_of_numpy(elements):
 
 
 def set_core_number(num):
-    callBigDlFunc("float", "setCoreNumber", num)
+    callZooFunc("float", "setCoreNumber", num)
+
+
+def callZooFunc(bigdl_type, name, *args):
+    """ Call API in PythonBigDL """
+    gateway = _get_gateway()
+    args = [_py2java(gateway, a) for a in args]
+    error = Exception("Cannot find function: %s" % name)
+    for jinvoker in JavaCreator.instance(bigdl_type, gateway).value:
+        # hasattr(jinvoker, name) always return true here,
+        # so you need to invoke the method to check if it exist or not
+        try:
+            api = getattr(jinvoker, name)
+            java_result = api(*args)
+            result = _java2py(gateway, java_result)
+        except Exception as e:
+            error = e
+            if "does not exist" not in str(e):
+                raise e
+        else:
+            return result
+    raise error
 
 
 class JTensor(BJTensor):