fix examples

Author: mengxr

examples/src/main/java/org/apache/spark/examples/ml/JavaDeveloperApiExample.java

@@ -211,7 +211,7 @@ public Vector predictRaw(Vector features) {
   public MyJavaLogisticRegressionModel copy() {
     MyJavaLogisticRegressionModel m =
         new MyJavaLogisticRegressionModel(parent_, fittingParamMap_, weights_);
-    Params$.MODULE$.inheritValues(this.paramMap(), this, m);
+    Params$.MODULE$.inheritValues(this.extractParamMap(), this, m);
     return m;
   }
 }

examples/src/main/scala/org/apache/spark/examples/ml/DeveloperApiExample.scala

@@ -174,11 +174,11 @@ private class MyLogisticRegressionModel(
    * Create a copy of the model.
    * The copy is shallow, except for the embedded paramMap, which gets a deep copy.
    *
-   * This is used for the defaul implementation of [[transform()]].
+   * This is used for the default implementation of [[transform()]].
    */
   override protected def copy(): MyLogisticRegressionModel = {
     val m = new MyLogisticRegressionModel(parent, fittingParamMap, weights)
-    Params.inheritValues(this.paramMap, this, m)
+    Params.inheritValues(extractParamMap(), this, m)
     m
   }
 }

mllib/src/main/scala/org/apache/spark/ml/param/params.scala

@@ -249,10 +249,17 @@ trait Params extends Identifiable with Serializable {
    * extra values from input into a flat param map, where the latter value is used if there exist
    * conflicts.
    */
-  protected final def extractParamMap(extraParamMap: ParamMap = ParamMap.empty): ParamMap = {
+  protected final def extractParamMap(extraParamMap: ParamMap): ParamMap = {
     defaultParamMap ++ paramMap ++ extraParamMap
   }
 
+  /**
+   * [[extractParamMap]] with no extra values.
+   */
+  protected final def extractParamMap(): ParamMap = {
+    extractParamMap(ParamMap.empty)
+  }
+
   /** Internal param map for user-supplied values. */
   private val paramMap: ParamMap = ParamMap.empty