From 507fb63bf580e32ea3ca35508a849d4105f3fe94 Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Wed, 12 Sep 2018 10:08:01 -0700
Subject: [PATCH 1/9] add initial commit for java NDArray

---
 .../main/scala/org/apache/mxnet/NDArray.scala | 49 +++++++++++++
 .../main/scala/org/apache/mxnet/Shape.scala   |  4 ++
 .../apache/mxnet/api/java/ArgBuilder.scala    | 69 +++++++++++++++++++
 3 files changed, 122 insertions(+)
 create mode 100644 scala-package/core/src/main/scala/org/apache/mxnet/api/java/ArgBuilder.scala

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
index 9b6a7dc66540..102233f8eb14 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
@@ -567,6 +567,55 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
     NDArrayCollector.collect(this)
   }
 
+  /**
+    * Java Flavor creating new NDArray
+    * @param arr
+    * @param shape
+    * @param ctx
+    * @return
+    */
+  def this(arr : Array[Float], shape : Shape, ctx : Context) = {
+    this(NDArray.newAllocHandle(shape, ctx, delayAlloc = false, Base.MX_REAL_TYPE))
+    this.set(arr)
+  }
+
+  override def toString: String = {
+    val arr = this.toArray
+    val shape = this.shape.toArray
+    buildStringHelper(0, arr.length - 1, arr, shape, 0) + "\n"
+  }
+
+  /**
+    * Helper function to create formatted NDArray output
+    * @param start starting position
+    * @param end ending position
+    * @param arr Float array of NDArray
+    * @param shape shape of NDArray
+    * @param dim current Dimension level of NDArray
+    * @return String format of NDArray
+    */
+  private def buildStringHelper(start : Int, end : Int, arr : Array[Float],
+                                shape : Array[Int], dim : Int) : String = {
+    var result = ""
+    if (dim != shape.length - 1) {
+      val length = shape(dim)
+      val fragment = (end - start + 1) / length
+      for (num <- 0 to length - 1) {
+        val output = buildStringHelper(start + fragment * num, start + fragment * (num + 1) - 1,
+          arr, shape, dim + 1)
+        result += s"$output\n"
+      }
+      result = s"${" " * dim}[\n$result${" " * dim}]"
+    } else {
+      var temp = ArrayBuffer[String]()
+      for (i <- start to end) {
+        temp += arr(i).toString
+      }
+      result = s"${" " * dim}[${temp.mkString(",")}]"
+    }
+    result
+  }
+
   // record arrays who construct this array instance
   // we use weak reference to prevent gc blocking
   private[mxnet] val dependencies = mutable.HashMap.empty[Long, WeakReference[NDArray]]
diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala b/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala
index 689176217722..c4c1c3167b03 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala
@@ -29,6 +29,10 @@ class Shape(dims: Traversable[Int]) extends Serializable {
     this(dims.toVector)
   }
 
+  def this(dims: Array[Int]) = {
+    this(dims.toVector)
+  }
+
   def apply(dim: Int): Int = shape(dim)
   def get(dim: Int): Int = apply(dim)
   def size: Int = shape.size
diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/api/java/ArgBuilder.scala b/scala-package/core/src/main/scala/org/apache/mxnet/api/java/ArgBuilder.scala
new file mode 100644
index 000000000000..4b478e5fc5dd
--- /dev/null
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/api/java/ArgBuilder.scala
@@ -0,0 +1,69 @@
+/*
+ * 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 org.apache.mxnet.api.java
+
+import scala.collection.mutable
+import scala.collection.mutable.ListBuffer
+import collection.JavaConverters._
+
+/**
+  * This arg Builder is intent to solve Java to Scala conversion
+  * to take the input such as (arg: Any*)
+  */
+class ArgBuilder {
+  private var data = ListBuffer[Any]()
+  private var map = mutable.Map[String, Any]()
+
+  def addArg(anyRef: AnyRef): ArgBuilder = {
+    require(map.isEmpty,
+      "Map is not empty, please do either key-value or positional-arg but not both")
+    this.data += anyRef.asInstanceOf[Any]
+    this
+  }
+
+  def addArg(key : String, value : AnyRef) : ArgBuilder = {
+    require(data.isEmpty,
+      "Data is not empty, please do either key-value or positional-arg but not both")
+    this.map(key) = value.asInstanceOf[Any]
+    this
+  }
+
+  def addBatchArgs(list : java.util.List[AnyRef]) : ArgBuilder = {
+    require(map.isEmpty,
+      "Map is not empty, please do either key-value or positional-arg but not both")
+    for (i <- 0 to list.size()) {
+      this.data += list.get(i)
+    }
+    this
+  }
+
+  def addBatchArgs(arr : Array[AnyRef]) : ArgBuilder = {
+    require(map.isEmpty,
+      "Map is not empty, please do either key-value or positional-arg but not both")
+    arr.foreach(ele => this.data += ele)
+    this
+  }
+
+  def buildMap() : Map[String, Any] = {
+    this.map.toMap
+  }
+
+  def buildSeq() : Seq[Any] = {
+    this.data
+  }
+}

From 61ed5f648738295f7134f4e307f671513c4943fb Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Wed, 12 Sep 2018 17:07:27 -0700
Subject: [PATCH 2/9] add operator named functions

---
 .../main/scala/org/apache/mxnet/NDArray.scala | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
index 102233f8eb14..dcb01f6a46e0 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
@@ -989,6 +989,44 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
     this
   }
 
+  /* Java Compatibility Functions
+     Function name with underscore means
+     it is going to do the operator as well as
+     update itself such as +=
+   */
+  def add(other : NDArray) : NDArray = this + other
+  def add(other : Float) : NDArray = this + other
+  def _add(other : NDArray) : NDArray = this += other
+  def _add(other : Float) : NDArray = this += other
+  def subtract(other : NDArray) : NDArray = this - other
+  def subtract(other : Float) : NDArray = this - other
+  def _subtract(other : NDArray) : NDArray = this -= other
+  def _subtract(other : Float) : NDArray = this -= other
+  def multiply(other : NDArray) : NDArray = this * other
+  def multiply(other : Float) : NDArray = this * other
+  def _multiply(other : NDArray) : NDArray = this *= other
+  def _multiply(other : Float) : NDArray = this *= other
+  def div(other : NDArray) : NDArray = this / other
+  def div(other : Float) : NDArray = this / other
+  def _div(other : NDArray) : NDArray = this /= other
+  def _div(other : Float) : NDArray = this /= other
+  def pow(other : NDArray) : NDArray = this ** other
+  def pow(other : Float) : NDArray = this ** other
+  def _pow(other : NDArray) : NDArray = this **= other
+  def _pow(other : Float) : NDArray = this **= other
+  def mod(other : NDArray) : NDArray = this % other
+  def mod(other : Float) : NDArray = this % other
+  def _mod(other : NDArray) : NDArray = this %= other
+  def _mod(other : Float) : NDArray = this %= other
+  def greater(other : NDArray) : NDArray = this > other
+  def greater(other : Float) : NDArray = this > other
+  def greaterEqual(other : NDArray) : NDArray = this >= other
+  def greaterEqual(other : Float) : NDArray = this >= other
+  def lesser(other : NDArray) : NDArray = this < other
+  def lesser(other : Float) : NDArray = this < other
+  def lesserEqual(other : NDArray) : NDArray = this <= other
+  def lesserEqual(other : Float) : NDArray = this <= other
+
   /**
    * Return a copied flat java array of current array (row-major).
    * @return  A copy of array content.

From 824b1cdcaa6320bf011dc2ca6b0f0221f3bda07e Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Thu, 13 Sep 2018 15:07:22 -0700
Subject: [PATCH 3/9] add support for using new Type-safe api

---
 .../api/java/Java2ScalaConversionKit.scala    | 34 +++++++++++++++++++
 .../scala/org/apache/mxnet/NDArrayMacro.scala |  6 ++--
 .../apache/mxnet/utils/CToScalaUtils.scala    | 10 +++---
 3 files changed, 43 insertions(+), 7 deletions(-)
 create mode 100644 scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala b/scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala
new file mode 100644
index 000000000000..9b2905b4b572
--- /dev/null
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala
@@ -0,0 +1,34 @@
+/*
+ * 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 org.apache.mxnet.api.java
+
+/**
+  * This kit is intend to bring Java user seamless experience
+  * Using Java to do what Scala have
+  */
+object Java2ScalaConversionKit {
+
+  /**
+    * Wrap a object with Option
+    * element => Option[element]
+    * @param element the input object
+    * @tparam A Type param
+    * @return Option[A]
+    */
+  def Option[A](element : A) : Option[A] = Some(element)
+
+}
diff --git a/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala b/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala
index 2d3a1c7ec5af..d87308f1ea7d 100644
--- a/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala
+++ b/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala
@@ -133,13 +133,15 @@ private[mxnet] object NDArrayMacro {
             "map(\"" + ndarrayarg.argName + "\") = " + currArgName
           }
         impl.append(
-          if (ndarrayarg.isOptional) s"if (!$currArgName.isEmpty) $base.get"
+          if (ndarrayarg.isOptional) {
+            s"if ($currArgName != null && !$currArgName.isEmpty) $base.get"
+          }
           else base
         )
       })
       // add default out parameter
       argDef += "out : Option[NDArray] = None"
-      impl += "if (!out.isEmpty) map(\"out\") = out.get"
+      impl += "if (out != null && !out.isEmpty) map(\"out\") = out.get"
       // scalastyle:off
       impl += "org.apache.mxnet.NDArray.genericNDArrayFunctionInvoke(\"" + ndarrayfunction.name + "\", args.toSeq, map.toMap)"
       // scalastyle:on
diff --git a/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala b/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala
index d0ebe5b1d2cb..19a54193cec0 100644
--- a/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala
+++ b/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala
@@ -28,12 +28,12 @@ private[mxnet] object CToScalaUtils {
       case "Symbol" | "NDArray" | "NDArray-or-Symbol" => returnType
       case "Symbol[]" | "NDArray[]" | "NDArray-or-Symbol[]" | "SymbolorSymbol[]"
       => s"Array[$returnType]"
-      case "float" | "real_t" | "floatorNone" => "org.apache.mxnet.Base.MXFloat"
-      case "int" | "intorNone" | "int(non-negative)" => "Int"
-      case "long" | "long(non-negative)" => "Long"
-      case "double" | "doubleorNone" => "Double"
+      case "float" | "real_t" | "floatorNone" => "java.lang.Float"
+      case "int" | "intorNone" | "int(non-negative)" => "java.lang.Integer"
+      case "long" | "long(non-negative)" => "java.lang.Long"
+      case "double" | "doubleorNone" => "java.lang.Double"
       case "string" => "String"
-      case "boolean" | "booleanorNone" => "Boolean"
+      case "boolean" | "booleanorNone" => "java.lang.Boolean"
       case "tupleof<float>" | "tupleof<double>" | "tupleof<>" | "ptr" | "" => "Any"
       case default => throw new IllegalArgumentException(
         s"Invalid type for args: $default\nString argType: $argType\nargName: $argName")

From 8aabde00413980b1d821c6d488c290430e6a05b7 Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Mon, 17 Sep 2018 09:59:33 -0700
Subject: [PATCH 4/9] fix Scala Macros failure

---
 .../macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala b/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala
index c3a7c58c1afc..4404b0885d57 100644
--- a/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala
+++ b/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala
@@ -36,7 +36,7 @@ class MacrosSuite extends FunSuite with BeforeAndAfterAll {
     )
     val output = List(
       ("org.apache.mxnet.Symbol", true),
-      ("Int", false),
+      ("java.lang.Integer", false),
       ("org.apache.mxnet.Shape", true),
       ("String", true),
       ("Any", false)

From d74f8812ed2b746125317c1162988831f6b25901 Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Mon, 17 Sep 2018 15:11:12 -0700
Subject: [PATCH 5/9] add Java compatible initialize methods and optimized
 toString

---
 .../main/scala/org/apache/mxnet/NDArray.scala | 55 ++++++++++++-------
 .../main/scala/org/apache/mxnet/Shape.scala   |  5 ++
 2 files changed, 39 insertions(+), 21 deletions(-)

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
index dcb01f6a46e0..639d7d446978 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
@@ -248,6 +248,11 @@ object NDArray extends NDArrayBase {
 
   def ones(ctx: Context, shape: Int *): NDArray = ones(Shape(shape: _*), ctx)
 
+  // Java compatible conversion methods
+  def empty(shape: Array[Int]): NDArray = empty(Shape(shape))
+  def zeros(shape: Array[Int]): NDArray = zeros(Shape(shape))
+  def ones(shape: Array[Int]) : NDArray = ones(Shape(shape))
+
   /**
    * Create a new NDArray filled with given value, with specified shape.
    * @param shape shape of the NDArray.
@@ -580,38 +585,44 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
   }
 
   override def toString: String = {
-    val arr = this.toArray
-    val shape = this.shape.toArray
-    buildStringHelper(0, arr.length - 1, arr, shape, 0) + "\n"
+    buildStringHelper(this, this.shape.length) + "\n"
   }
 
   /**
     * Helper function to create formatted NDArray output
-    * @param start starting position
-    * @param end ending position
-    * @param arr Float array of NDArray
-    * @param shape shape of NDArray
-    * @param dim current Dimension level of NDArray
+    * The NDArray will be represented in a reduced version if too large
+    * @param nd NDArray as the input
+    * @param totalSpace totalSpace of the lowest dimension
     * @return String format of NDArray
     */
-  private def buildStringHelper(start : Int, end : Int, arr : Array[Float],
-                                shape : Array[Int], dim : Int) : String = {
+  private def buildStringHelper(nd : NDArray, totalSpace : Int) : String = {
     var result = ""
-    if (dim != shape.length - 1) {
-      val length = shape(dim)
-      val fragment = (end - start + 1) / length
-      for (num <- 0 to length - 1) {
-        val output = buildStringHelper(start + fragment * num, start + fragment * (num + 1) - 1,
-          arr, shape, dim + 1)
+    val THRESHOLD = 100000      // longest NDArray to show in full
+    val ARRAYTHRESHOLD = 1000   // longest array to show in full
+    val shape = nd.shape
+    val space = totalSpace - shape.length
+    if (shape.length != 1) {
+      val (length, postfix) =
+        if (shape.product > THRESHOLD) {
+          // reduced NDArray
+          (1, s"\n${" " * (space + 1)}... with length ${shape(0)}\n")
+      } else {
+          (shape(0), "")
+        }
+      for (num <- 0 until length) {
+        val output = buildStringHelper(nd.at(num), totalSpace)
         result += s"$output\n"
       }
-      result = s"${" " * dim}[\n$result${" " * dim}]"
+      result = s"${" " * space}[\n$result${" " * space}$postfix]"
     } else {
-      var temp = ArrayBuffer[String]()
-      for (i <- start to end) {
-        temp += arr(i).toString
+      if (shape(0) > ARRAYTHRESHOLD) {
+        // reduced Array
+        val front = nd.slice(0, 10)
+        val back = nd.slice(shape(0) - 10, shape(0) - 1)
+        result = s"${" " * space}[${front.toArray.mkString(",")} ... ${back.toArray.mkString(",")}]"
+      } else {
+        result = s"${" " * space}[${nd.toArray.mkString(",")}]"
       }
-      result = s"${" " * dim}[${temp.mkString(",")}]"
     }
     result
   }
@@ -1032,6 +1043,8 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
    * @return  A copy of array content.
    */
   def toArray: Array[Float] = {
+    require(shape.toArray.product < 1000000,
+      "NDArray size is too large, consider reducing the dimension")
     internal.toFloatArray
   }
 
diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala b/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala
index c4c1c3167b03..772ec8e262c1 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/Shape.scala
@@ -29,6 +29,11 @@ class Shape(dims: Traversable[Int]) extends Serializable {
     this(dims.toVector)
   }
 
+  /**
+    * Java compatible constructor
+    * @param dims Array of Int input
+    * @return Shape
+    */
   def this(dims: Array[Int]) = {
     this(dims.toVector)
   }

From ca27685ef35dc2a9e5506ee7e622de409855354b Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Tue, 18 Sep 2018 15:33:02 -0700
Subject: [PATCH 6/9] remove the require field and rename the toString method

---
 .../core/src/main/scala/org/apache/mxnet/NDArray.scala    | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
index 639d7d446978..b31806d45b1d 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
@@ -584,7 +584,11 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
     this.set(arr)
   }
 
-  override def toString: String = {
+  /**
+    * Visualize the internal structure of NDArray
+    * @return String that show the structure
+    */
+  def visualize: String = {
     buildStringHelper(this, this.shape.length) + "\n"
   }
 
@@ -1043,8 +1047,6 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
    * @return  A copy of array content.
    */
   def toArray: Array[Float] = {
-    require(shape.toArray.product < 1000000,
-      "NDArray size is too large, consider reducing the dimension")
     internal.toFloatArray
   }
 

From 4cb03d676cb7d7384b32fd02c350bb846cba9485 Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Wed, 19 Sep 2018 15:50:06 -0700
Subject: [PATCH 7/9] revert changes on Macros and will apply in different PR

---
 .../api/java/Java2ScalaConversionKit.scala    | 34 -------------------
 .../scala/org/apache/mxnet/NDArrayMacro.scala |  6 ++--
 .../apache/mxnet/utils/CToScalaUtils.scala    | 10 +++---
 .../scala/org/apache/mxnet/MacrosSuite.scala  |  2 +-
 4 files changed, 8 insertions(+), 44 deletions(-)
 delete mode 100644 scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala b/scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala
deleted file mode 100644
index 9b2905b4b572..000000000000
--- a/scala-package/core/src/main/scala/org/apache/mxnet/api/java/Java2ScalaConversionKit.scala
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * 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 org.apache.mxnet.api.java
-
-/**
-  * This kit is intend to bring Java user seamless experience
-  * Using Java to do what Scala have
-  */
-object Java2ScalaConversionKit {
-
-  /**
-    * Wrap a object with Option
-    * element => Option[element]
-    * @param element the input object
-    * @tparam A Type param
-    * @return Option[A]
-    */
-  def Option[A](element : A) : Option[A] = Some(element)
-
-}
diff --git a/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala b/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala
index d87308f1ea7d..2d3a1c7ec5af 100644
--- a/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala
+++ b/scala-package/macros/src/main/scala/org/apache/mxnet/NDArrayMacro.scala
@@ -133,15 +133,13 @@ private[mxnet] object NDArrayMacro {
             "map(\"" + ndarrayarg.argName + "\") = " + currArgName
           }
         impl.append(
-          if (ndarrayarg.isOptional) {
-            s"if ($currArgName != null && !$currArgName.isEmpty) $base.get"
-          }
+          if (ndarrayarg.isOptional) s"if (!$currArgName.isEmpty) $base.get"
           else base
         )
       })
       // add default out parameter
       argDef += "out : Option[NDArray] = None"
-      impl += "if (out != null && !out.isEmpty) map(\"out\") = out.get"
+      impl += "if (!out.isEmpty) map(\"out\") = out.get"
       // scalastyle:off
       impl += "org.apache.mxnet.NDArray.genericNDArrayFunctionInvoke(\"" + ndarrayfunction.name + "\", args.toSeq, map.toMap)"
       // scalastyle:on
diff --git a/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala b/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala
index 19a54193cec0..d0ebe5b1d2cb 100644
--- a/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala
+++ b/scala-package/macros/src/main/scala/org/apache/mxnet/utils/CToScalaUtils.scala
@@ -28,12 +28,12 @@ private[mxnet] object CToScalaUtils {
       case "Symbol" | "NDArray" | "NDArray-or-Symbol" => returnType
       case "Symbol[]" | "NDArray[]" | "NDArray-or-Symbol[]" | "SymbolorSymbol[]"
       => s"Array[$returnType]"
-      case "float" | "real_t" | "floatorNone" => "java.lang.Float"
-      case "int" | "intorNone" | "int(non-negative)" => "java.lang.Integer"
-      case "long" | "long(non-negative)" => "java.lang.Long"
-      case "double" | "doubleorNone" => "java.lang.Double"
+      case "float" | "real_t" | "floatorNone" => "org.apache.mxnet.Base.MXFloat"
+      case "int" | "intorNone" | "int(non-negative)" => "Int"
+      case "long" | "long(non-negative)" => "Long"
+      case "double" | "doubleorNone" => "Double"
       case "string" => "String"
-      case "boolean" | "booleanorNone" => "java.lang.Boolean"
+      case "boolean" | "booleanorNone" => "Boolean"
       case "tupleof<float>" | "tupleof<double>" | "tupleof<>" | "ptr" | "" => "Any"
       case default => throw new IllegalArgumentException(
         s"Invalid type for args: $default\nString argType: $argType\nargName: $argName")
diff --git a/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala b/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala
index 4404b0885d57..c3a7c58c1afc 100644
--- a/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala
+++ b/scala-package/macros/src/test/scala/org/apache/mxnet/MacrosSuite.scala
@@ -36,7 +36,7 @@ class MacrosSuite extends FunSuite with BeforeAndAfterAll {
     )
     val output = List(
       ("org.apache.mxnet.Symbol", true),
-      ("java.lang.Integer", false),
+      ("Int", false),
       ("org.apache.mxnet.Shape", true),
       ("String", true),
       ("Any", false)

From 494b7b5e6446ed201cc468b2015f5d21319e6fa0 Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Thu, 20 Sep 2018 11:27:08 -0700
Subject: [PATCH 8/9] adding new NDArray test

---
 .../core/src/test/scala/org/apache/mxnet/NDArraySuite.scala  | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scala-package/core/src/test/scala/org/apache/mxnet/NDArraySuite.scala b/scala-package/core/src/test/scala/org/apache/mxnet/NDArraySuite.scala
index 5d88bb39e502..edbc98e5a11a 100644
--- a/scala-package/core/src/test/scala/org/apache/mxnet/NDArraySuite.scala
+++ b/scala-package/core/src/test/scala/org/apache/mxnet/NDArraySuite.scala
@@ -38,6 +38,11 @@ class NDArraySuite extends FunSuite with BeforeAndAfterAll with Matchers {
     assert(ndones.toScalar === 1f)
   }
 
+  test("new NDArray") {
+    val ndarray = new NDArray(Array(1.0f, 2.0f), Shape(1, 2), Context.cpu())
+    assert(ndarray.shape == Shape(1, 2))
+  }
+
   test ("call toScalar on an ndarray which is not a scalar") {
     intercept[Exception] { NDArray.zeros(1, 1).toScalar }
   }

From bf8792df76cc5672b63c37cea7f6a8ed47e62780 Mon Sep 17 00:00:00 2001
From: Qing <lanking520@live.com>
Date: Thu, 27 Sep 2018 10:12:12 -0700
Subject: [PATCH 9/9] remove unrelated method to Java

---
 .../main/scala/org/apache/mxnet/NDArray.scala | 47 -------------------
 1 file changed, 47 deletions(-)

diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
index b31806d45b1d..dc1273315b24 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
@@ -584,53 +584,6 @@ class NDArray private[mxnet](private[mxnet] val handle: NDArrayHandle,
     this.set(arr)
   }
 
-  /**
-    * Visualize the internal structure of NDArray
-    * @return String that show the structure
-    */
-  def visualize: String = {
-    buildStringHelper(this, this.shape.length) + "\n"
-  }
-
-  /**
-    * Helper function to create formatted NDArray output
-    * The NDArray will be represented in a reduced version if too large
-    * @param nd NDArray as the input
-    * @param totalSpace totalSpace of the lowest dimension
-    * @return String format of NDArray
-    */
-  private def buildStringHelper(nd : NDArray, totalSpace : Int) : String = {
-    var result = ""
-    val THRESHOLD = 100000      // longest NDArray to show in full
-    val ARRAYTHRESHOLD = 1000   // longest array to show in full
-    val shape = nd.shape
-    val space = totalSpace - shape.length
-    if (shape.length != 1) {
-      val (length, postfix) =
-        if (shape.product > THRESHOLD) {
-          // reduced NDArray
-          (1, s"\n${" " * (space + 1)}... with length ${shape(0)}\n")
-      } else {
-          (shape(0), "")
-        }
-      for (num <- 0 until length) {
-        val output = buildStringHelper(nd.at(num), totalSpace)
-        result += s"$output\n"
-      }
-      result = s"${" " * space}[\n$result${" " * space}$postfix]"
-    } else {
-      if (shape(0) > ARRAYTHRESHOLD) {
-        // reduced Array
-        val front = nd.slice(0, 10)
-        val back = nd.slice(shape(0) - 10, shape(0) - 1)
-        result = s"${" " * space}[${front.toArray.mkString(",")} ... ${back.toArray.mkString(",")}]"
-      } else {
-        result = s"${" " * space}[${nd.toArray.mkString(",")}]"
-      }
-    }
-    result
-  }
-
   // record arrays who construct this array instance
   // we use weak reference to prevent gc blocking
   private[mxnet] val dependencies = mutable.HashMap.empty[Long, WeakReference[NDArray]]