[SPARK-13550][ML] Add java example for ml.clustering.BisectingKMeans

JIRA: https://issues.apache.org/jira/browse/SPARK-13550

## What changes were proposed in this pull request?

Just add a java example for ml.clustering.BisectingKMeans

## How was this patch tested?

manual tests were done.

(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #11428 from zhengruifeng/ml_bkm_je.

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

+/*
+ * 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.spark.examples.ml;
+
+import java.util.Arrays;
+
+import org.apache.spark.SparkConf;
+import org.apache.spark.api.java.JavaRDD;
+import org.apache.spark.api.java.JavaSparkContext;
+import org.apache.spark.sql.RowFactory;
+import org.apache.spark.sql.SQLContext;
+// $example on$
+import org.apache.spark.ml.clustering.BisectingKMeans;
+import org.apache.spark.ml.clustering.BisectingKMeansModel;
+import org.apache.spark.mllib.linalg.Vector;
+import org.apache.spark.mllib.linalg.VectorUDT;
+import org.apache.spark.mllib.linalg.Vectors;
+import org.apache.spark.sql.DataFrame;
+import org.apache.spark.sql.Row;
+import org.apache.spark.sql.types.Metadata;
+import org.apache.spark.sql.types.StructField;
+import org.apache.spark.sql.types.StructType;
+// $example off$
+
+
+/**
+ * An example demonstrating a bisecting k-means clustering.
+ */
+public class JavaBisectingKMeansExample {
+
+  public static void main(String[] args) {
+    SparkConf conf = new SparkConf().setAppName("JavaBisectingKMeansExample");
+    JavaSparkContext jsc = new JavaSparkContext(conf);
+    SQLContext jsql = new SQLContext(jsc);
+
+    // $example on$
+    JavaRDD<Row> data = jsc.parallelize(Arrays.asList(
+      RowFactory.create(Vectors.dense(0.1, 0.1, 0.1)),
+      RowFactory.create(Vectors.dense(0.3, 0.3, 0.25)),
+      RowFactory.create(Vectors.dense(0.1, 0.1, -0.1)),
+      RowFactory.create(Vectors.dense(20.3, 20.1, 19.9)),
+      RowFactory.create(Vectors.dense(20.2, 20.1, 19.7)),
+      RowFactory.create(Vectors.dense(18.9, 20.0, 19.7))
+    ));
+
+    StructType schema = new StructType(new StructField[]{
+      new StructField("features", new VectorUDT(), false, Metadata.empty()),
+    });
+
+    DataFrame dataset = jsql.createDataFrame(data, schema);
+
+    BisectingKMeans bkm = new BisectingKMeans().setK(2);
+    BisectingKMeansModel model = bkm.fit(dataset);
+
+    System.out.println("Compute Cost: " + model.computeCost(dataset));
+
+    Vector[] clusterCenters = model.clusterCenters();
+    for (int i = 0; i < clusterCenters.length; i++) {
+      Vector clusterCenter = clusterCenters[i];
+      System.out.println("Cluster Center " + i + ": " + clusterCenter);
+    }
+    // $example off$
+
+    jsc.stop();
+  }
+}