diff --git a/extensions/jython/src/com/google/refine/jython/JythonEvaluable.java b/extensions/jython/src/com/google/refine/jython/JythonEvaluable.java
index 2b96794c8..70bcfdb53 100644
--- a/extensions/jython/src/com/google/refine/jython/JythonEvaluable.java
+++ b/extensions/jython/src/com/google/refine/jython/JythonEvaluable.java
@@ -33,29 +33,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 package com.google.refine.jython;
 
+import com.google.refine.expr.*;
+import org.python.core.*;
+import org.python.util.PythonInterpreter;
+
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Properties;
 
-import org.python.core.Py;
-import org.python.core.PyException;
-import org.python.core.PyFloat;
-import org.python.core.PyFunction;
-import org.python.core.PyInteger;
-import org.python.core.PyLong;
-import org.python.core.PyNone;
-import org.python.core.PyObject;
-import org.python.core.PyString;
-import org.python.util.PythonInterpreter;
-
-import com.google.refine.expr.EvalError;
-import com.google.refine.expr.Evaluable;
-import com.google.refine.expr.HasFields;
-import com.google.refine.expr.LanguageSpecificParser;
-import com.google.refine.expr.ParsingException;
-
 public class JythonEvaluable implements Evaluable {
     
     static public LanguageSpecificParser createParser() {
@@ -68,7 +55,7 @@ public class JythonEvaluable implements Evaluable {
         };
     }
     
-    private static final String s_functionName = "___temp___";
+    private final String s_functionName;
     
     private static PythonInterpreter _engine; 
     
@@ -97,6 +84,8 @@ public class JythonEvaluable implements Evaluable {
     }
 
     public JythonEvaluable(String s) {
+        this.s_functionName = String.format("__temp_%d__", Math.abs(s.hashCode()));
+
         // indent and create a function out of the code
         String[] lines = s.split("\r\n|\r|\n");
         
diff --git a/extensions/jython/tests/com/google/refine/jython/JythonEvaluableTest.java b/extensions/jython/tests/com/google/refine/jython/JythonEvaluableTest.java
new file mode 100644
index 000000000..a9aec0993
--- /dev/null
+++ b/extensions/jython/tests/com/google/refine/jython/JythonEvaluableTest.java
@@ -0,0 +1,47 @@
+package com.google.refine.jython;
+
+import com.google.refine.expr.CellTuple;
+import com.google.refine.expr.Evaluable;
+import com.google.refine.model.Cell;
+import com.google.refine.model.Project;
+import com.google.refine.model.Row;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.util.Properties;
+
+/**
+ * @author Maxim Galushka
+ */
+public class JythonEvaluableTest {
+
+  @Test
+  public void testJythonConcurrent(){
+    Properties props = new Properties();
+    Project project = new Project();
+
+    Row row = new Row(2);
+    row.setCell(0, new Cell("one", null));
+    row.setCell(0, new Cell("1", null));
+
+    props.put("columnName", "number");
+    props.put("true", "true");
+    props.put("false", "false");
+    props.put("rowIndex", "0");
+    props.put("value", 1);
+    props.put("project", project);
+    props.put("call", "number");
+    props.put("PI", "3.141592654");
+    props.put("cells", new CellTuple(project, row));
+
+    Evaluable eval1 = new JythonEvaluable("a = value\nreturn a * 2");
+    Long value1 = (Long) eval1.evaluate(props);
+
+    // create some unrelated evaluable
+    new JythonEvaluable("a = value\nreturn a * 10");
+
+    // repeat same previous test
+    Long value2 = (Long) eval1.evaluate(props);
+    Assert.assertEquals(value1, value2);
+  }
+}