diff --git a/datafu-spark/src/main/java/datafu/spark/SparkUDF.java b/datafu-spark/src/main/java/datafu/spark/SparkUDF.java
new file mode 100644
index 00000000..67c2caaf
--- /dev/null
+++ b/datafu-spark/src/main/java/datafu/spark/SparkUDF.java
@@ -0,0 +1,11 @@
+package datafu.spark;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.METHOD})
+public @interface SparkUDF {
+}
\ No newline at end of file
diff --git a/datafu-spark/src/main/resources/pyspark_utils/bridge_utils.py b/datafu-spark/src/main/resources/pyspark_utils/bridge_utils.py
index 40134d00..5529fd00 100644
--- a/datafu-spark/src/main/resources/pyspark_utils/bridge_utils.py
+++ b/datafu-spark/src/main/resources/pyspark_utils/bridge_utils.py
@@ -26,6 +26,12 @@
 def _getjvm_class(gateway, fullClassName):
     return gateway.jvm.java.lang.Thread.currentThread().getContextClassLoader().loadClass(fullClassName).newInstance()
 
+def UDFRegister(sqlContext, clazz):
+    # Registers all SQL user-defined functions. Calls Scala for registration.
+    sc = sqlContext._sc
+    gateway = sc._gateway
+    ureg = gateway.jvm.datafu.spark.UDFRegister
+    ureg.registerObject(clazz, sqlContext._jsqlContext)
 
 class Context(object):
 
diff --git a/datafu-spark/src/main/scala/datafu/spark/SparkUDFs.scala b/datafu-spark/src/main/scala/datafu/spark/SparkUDFs.scala
new file mode 100644
index 00000000..18836e12
--- /dev/null
+++ b/datafu-spark/src/main/scala/datafu/spark/SparkUDFs.scala
@@ -0,0 +1,192 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package datafu.spark
+
+import org.apache.commons.lang3.StringUtils
+import org.apache.spark.sql.SQLContext
+import org.apache.spark.sql.catalyst.ScalaReflection
+import org.apache.spark.sql.catalyst.analysis.FunctionRegistry.FunctionBuilder
+import org.apache.spark.sql.catalyst.expressions.{Expression, ScalaUDF}
+import org.apache.spark.sql.expressions.UserDefinedFunction
+import org.apache.spark.sql.functions.udf
+import org.apache.spark.sql.types.DataType
+
+import scala.collection.mutable
+import scala.reflect.runtime.universe
+
+object SparkUDFs {
+
+  /**
+    * given an elem and array of values, return false if element is empty or if the array contains element
+    */
+  private def isEmptyWithDefaultFunc(emptyVals: Seq[Any] = Seq.empty, elem: String)= {
+    StringUtils.isEmpty(elem) || emptyVals.contains(elem)
+  }
+
+  val isEmptyWithDefault: UserDefinedFunction = udf((emptyVals: Seq[Any], elem: String)=>{
+    isEmptyWithDefaultFunc(emptyVals, elem)
+  })
+
+  val isNoneBlank: UserDefinedFunction = udf((elem: String)=>{
+    StringUtils.isNoneBlank(elem)
+  })
+
+  val isBlank: UserDefinedFunction = udf((elem: String)=>{
+    StringUtils.isBlank(elem)
+  })
+
+  /**
+    * like null-coalesce but returning the first not empty value:
+    * coalesceVal(null, "a") -> "a"
+    * coalesceVal("", "a") -> "a"
+    */
+  @SparkUDF
+  def coalesceVal(s1: String, s2: String)  = {
+    Array(s1, s2).foldLeft[String](null)((b, s) => Option(b).getOrElse("") match {
+      case "" => s
+      case _ => b
+    })
+  }
+
+  /**
+    * like null-coalesce but returning the first not empty value:
+    * coalesceVal(null, "a") -> "a"
+    * coalesceVal("", "a") -> "a"
+    */
+  def coalesceValUDF: UserDefinedFunction = udf((s1: String, s2: String) => {
+
+    SparkUDFs.coalesceVal(s1,s2)
+
+  })
+}
+
+object UDFRegister {
+  def register(sqlContext: SQLContext) = {
+    new UDFRegister().register(sqlContext)
+  }
+
+  def register(clazz: Class[_], sqlContext: SQLContext) = {
+    new UDFRegister().registerScalaClass(isScalaObject = false, clazz.getName, sqlContext)
+  }
+
+  def registerObject(clazz: String, sqlContext: SQLContext) = {
+    new UDFRegister().registerScalaClass(isScalaObject = true, clazz, sqlContext)
+  }
+
+  def registerObject(clazz: Class[_], sqlContext: SQLContext) = {
+    new UDFRegister().registerScalaClass(isScalaObject = true, clazz.getName, sqlContext)
+  }
+}
+
+class UDFRegister() extends Serializable {
+
+  /**
+    * This method is called from pyspark/zeppelin
+    * import pyspark_utils.utils
+    * utils.UDFRegister(sqlContext)  # passing the sqlContext provided by Zeppelin
+    * # UDFRegister calls this function
+    *
+    * @param sqlContext
+    */
+  def register(sqlContext: SQLContext) = {
+    /**
+      * Add lines here for the objects/classes that contain Scala UDFs
+      * For an Object use registerScalaObject(MyObject.getClass, sqlContext)
+      * For a class use registerScalaClass(typeOf[MyClass], sqlContext)
+      */
+    registerScalaClass(isScalaObject = true, SparkUDFs.getClass.getName, sqlContext)
+  }
+
+  def registerScalaClass(isScalaObject: Boolean, cname: String, sqlContext: SQLContext): Unit = {
+    // Note - we have looked int Scala reflection, Universe, Tree, Toolbox etc.
+    //  and we decide to use low level Java-like interface as the Toolbox
+    // package requires a dependency on the scala-compiler.jar
+
+    val loader = getClass.getClassLoader
+    val z = loader.loadClass(cname)
+    val methods = z.getMethods
+    val annotatedMethods = methods.withFilter { m =>
+      m.getAnnotation(classOf[SparkUDF]) != null
+    }
+
+    annotatedMethods.foreach(am => {
+      val name = am.getName
+      val retClz: Class[_] = am.getReturnType
+      val np: Int = am.getParameterTypes.length
+      try {
+        val func: AnyRef = np match {
+          case 0 => () => invokeByName(isScalaObject, cname, name, Array[Any](name))
+          case 1 => a: Any => invokeByName(isScalaObject, cname, name, Array[Any](a))
+          case 2 => (a: Any, b: Any) => invokeByName(isScalaObject, cname, name, Array[Any](a, b))
+          case 3 => (a: Any, b: Any, c: Any) => invokeByName(isScalaObject, cname, name, Array[Any](a, b, c))
+          case 4 => (a: Any, b: Any, c: Any, d: Any) => invokeByName(isScalaObject, cname, name, Array[Any](a, b, c, d))
+          case 5 => (a: Any, b: Any, c: Any, d: Any, e: Any) => invokeByName(isScalaObject, cname, name, Array[Any](a, b, c, d, e))
+          case 6 => (a: Any, b: Any, c: Any, d: Any, e: Any, f: Any) => invokeByName(isScalaObject, cname, name, Array[Any](a, b, c, d, e, f))
+        }
+        // convert from scala method to spark UDF
+        val builder = (e: Seq[Expression]) => {
+          val loader = getClass.getClassLoader
+          val mirror = scala.reflect.runtime.universe.runtimeMirror(loader)
+          val dataType: DataType = ScalaReflection.schemaFor(getType(retClz, mirror)).dataType
+          val inputsNullSafe: Seq[Boolean] = am.getParameterTypes.map(clz => false).toSeq
+          val inputTypes: Seq[DataType] = am.getParameterTypes.map(clz => ScalaReflection.schemaFor(getType(clz, mirror)).dataType).toSeq
+          ScalaUDF(func, dataType, e, inputsNullSafe, inputTypes)
+ //         org.apache.spark.sql.catalyst.expressions.ScalaUDF(function = func, dataType = dataType, children = e, inputTypes = inputTypes)
+
+
+        }
+        registerFunctionBuilder(sqlContext, name, builder)
+      } catch {
+        case e: Exception => println(e)
+      }
+    })
+  }
+
+  def invokeByNameObject(isScalaObject: Boolean, className: String, methodName: String, params: Array[Object]): Any = {
+    // because of serialization problem - we cannot have java.lang.reflect.Method
+    // sent as part of the clojure.
+    // So we send the name of the class and method and use the class loader on each executor to find them.
+    val clazz = Thread.currentThread().getContextClassLoader.loadClass(className)
+    val instance = if (isScalaObject) {
+      // if we register from Scala we have this MODULE$ field. but if we register from python we don't.
+      val fields = clazz.getFields.filter(f => f.getName == "MODULE$")
+      if (fields.length == 0)
+        null
+      else fields.head.get(null)
+    } else clazz.newInstance()
+
+    val methods: Array[java.lang.reflect.Method] = clazz.getDeclaredMethods.filter(m => m.getName == methodName)
+    if (methods.length == 1) {
+      methods(0).invoke(instance, params: _*)
+    } else {
+      throw new RuntimeException("SPARK UDF - must have only a single function defined with name " + methodName)
+    }
+  }
+
+  def invokeByName(isScalaObject: Boolean, className: String, methodName: String, params: Array[Any]): Any = {
+    invokeByNameObject(isScalaObject, className, methodName, params.map(_.asInstanceOf[Object]))
+  }
+
+  def getType(clazz: Class[_], runtimeMirror: scala.reflect.runtime.universe.Mirror): universe.Type =
+    runtimeMirror.classSymbol(clazz).toType
+
+  def registerFunctionBuilder(sqlContext : SQLContext, name : String, builder: FunctionBuilder): Unit = {
+    sqlContext.sparkSession.sessionState.functionRegistry.createOrReplaceTempFunction(name, builder)
+  }
+}
diff --git a/datafu-spark/src/test/resources/python_tests/pyfromscala.py b/datafu-spark/src/test/resources/python_tests/pyfromscala.py
index 03fcf929..218896e1 100644
--- a/datafu-spark/src/test/resources/python_tests/pyfromscala.py
+++ b/datafu-spark/src/test/resources/python_tests/pyfromscala.py
@@ -24,6 +24,7 @@
 from pprint import pprint as p
 p(sys.path)
 
+from pyspark_utils.bridge_utils import UDFRegister
 from pyspark.sql import functions as F
 
 
@@ -42,6 +43,11 @@
 
 sqlContext.sql("select d * 4 as d from dfout").registerTempTable("dfout2")
 
+###############################################################
+# check scala UDFs
+###############################################################
+UDFRegister(sqlContext, "datafu.spark.SparkUDFs")
+sqlContext.sql("select coalesceVal('', 'asd')").show()
 
 ###############################################################
 # check python UDFs
diff --git a/datafu-spark/src/test/scala/datafu/spark/TestSparkUDFs.scala b/datafu-spark/src/test/scala/datafu/spark/TestSparkUDFs.scala
new file mode 100644
index 00000000..0307c640
--- /dev/null
+++ b/datafu-spark/src/test/scala/datafu/spark/TestSparkUDFs.scala
@@ -0,0 +1,99 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package datafu.spark
+
+import com.holdenkarau.spark.testing.DataFrameSuiteBase
+import org.apache.spark.SparkConf
+import org.apache.spark.sql.{DataFrame, Row}
+import org.apache.spark.sql.datafu.types.SparkOverwriteUDAFs
+import org.apache.spark.sql.expressions.Window
+import org.apache.spark.sql.internal.StaticSQLConf.CATALOG_IMPLEMENTATION
+import org.apache.spark.sql.types._
+import org.apache.spark.sql.functions.{expr, _}
+import org.junit.Assert
+import org.junit.runner.RunWith
+import org.scalatest.FunSuite
+import org.scalatest.junit.JUnitRunner
+import org.slf4j.LoggerFactory
+
+@RunWith(classOf[JUnitRunner])
+class UdfTests extends FunSuite with DataFrameSuiteBase {
+
+  import spark.implicits._
+
+  /**
+    * taken from https://github.com/holdenk/spark-testing-base/issues/234#issuecomment-390150835
+    *
+    * Solves problem with Hive in Spark 2.3.0 in spark-testing-base
+    */
+  override def conf: SparkConf =
+    super.conf.set(CATALOG_IMPLEMENTATION.key, "hive")
+
+  val logger = LoggerFactory.getLogger(this.getClass)
+
+  val inputSchema = List(
+    StructField("col_ord", IntegerType, false),
+    StructField("col_str", StringType, true)
+  )
+
+  lazy val inputRDD = sc.parallelize(
+    Seq(Row(1, null),
+        Row(2, ""),
+        Row(3, "  "),
+        Row(1, "asd4")))
+
+  lazy val df =
+    sqlContext.createDataFrame(inputRDD, StructType(inputSchema)).cache
+
+
+  test("coalesceVal") {
+
+    val actual = df.withColumn("col_str", SparkUDFs.coalesceValUDF($"col_str", lit("newVal")))
+
+    val expected = sqlContext.createDataFrame(sc.parallelize(
+        Seq(Row(1, "newVal"),
+            Row(2, "newVal"),
+            Row(3, "asd3"),
+            Row(1, "asd4"))), StructType(inputSchema))
+
+    //assertDataFrameEquals(expected, actual)
+
+    expected.show()
+
+    Assert.assertEquals("asd", SparkUDFs.coalesceVal("asd", "eqw"))
+    Assert.assertEquals("eqw", SparkUDFs.coalesceVal(null, "eqw"))
+    Assert.assertEquals("asd", SparkUDFs.coalesceVal("asd", null))
+    //    Assert.assertEquals(null, SparkUDFs.coalesceVal(null, null))
+    Assert.assertEquals("eqw", SparkUDFs.coalesceVal("", "eqw"))
+    Assert.assertEquals("asd", SparkUDFs.coalesceVal("asd", ""))
+    Assert.assertEquals("", SparkUDFs.coalesceVal(null, ""))
+
+  }
+
+  test("registered_udf") {
+
+    UDFRegister.register(spark.sqlContext)
+
+    //spark.udf.register("coalesceVal", SparkUDFs.coalesceVal _)
+    val df = spark.sql("select coalesceVal('','asd')")
+
+    Assert.assertEquals("asd", df.first().get(0))
+  }
+
+}