## What changes were proposed in this pull request?

- A separate subsection for Aggregations under “Getting Started” in the Spark SQL programming guide. It mentions which aggregate functions are predefined and how users can create their own.
- Examples of using the `UserDefinedAggregateFunction` abstract class for untyped aggregations in Java and Scala.
- Examples of using the `Aggregator` abstract class for type-safe aggregations in Java and Scala.
- Python is not covered.
- The PR might not resolve the ticket since I do not know what exactly was planned by the author.

In total, there are four new standalone examples that can be executed via `spark-submit` or `run-example`. The updated Spark SQL programming guide references to these examples and does not contain hard-coded snippets.

## How was this patch tested?

The patch was tested locally by building the docs. The examples were run as well.

![image](https://cloud.githubusercontent.com/assets/6235869/21292915/04d9d084-c515-11e6-811a-999d598dffba.png)

Author: aokolnychyi <okolnychyyanton@gmail.com>

Closes #16329 from aokolnychyi/SPARK-16046.

## What changes were proposed in this pull request?
remove ununsed imports and outdated comments, and fix some minor code style issue.

## How was this patch tested?
existing ut

Author: uncleGen <hustyugm@gmail.com>

Closes #16591 from uncleGen/SPARK-19227.

## What changes were proposed in this pull request?
```ml.R``` example depends on ```e1071``` package, if it's not available in users' environment, it will fail. I think the example should not depends on third-party packages, so I update it to remove the dependency.

## How was this patch tested?
Manual test.

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #16548 from yanboliang/spark-19158.

## What changes were proposed in this pull request?

**binary_classification_metrics_example.py**

LibSVM datasource loads `ml.linalg.SparseVector` whereas the example requires it to be `mllib.linalg.SparseVector`.  For the equivalent Scala exmaple, `BinaryClassificationMetricsExample.scala` seems fine.

```
./bin/spark-submit examples/src/main/python/mllib/binary_classification_metrics_example.py
```

```
  File ".../spark/examples/src/main/python/mllib/binary_classification_metrics_example.py", line 39, in <lambda>
    .rdd.map(lambda row: LabeledPoint(row[0], row[1]))
  File ".../spark/python/pyspark/mllib/regression.py", line 54, in __init__
    self.features = _convert_to_vector(features)
  File ".../spark/python/pyspark/mllib/linalg/__init__.py", line 80, in _convert_to_vector
    raise TypeError("Cannot convert type %s into Vector" % type(l))
TypeError: Cannot convert type <class 'pyspark.ml.linalg.SparseVector'> into Vector
```

**status_api_demo.py** (this one does not work on Python 3.4.6)

It's `queue` in Python 3+.

```
PYSPARK_PYTHON=python3 ./bin/spark-submit examples/src/main/python/status_api_demo.py
```

```
Traceback (most recent call last):
  File ".../spark/examples/src/main/python/status_api_demo.py", line 22, in <module>
    import Queue
ImportError: No module named 'Queue'
```

**bisecting_k_means_example.py**

`BisectingKMeansModel` does not implement `save` and `load` in Python.

```bash
./bin/spark-submit examples/src/main/python/mllib/bisecting_k_means_example.py
```

```
Traceback (most recent call last):
  File ".../spark/examples/src/main/python/mllib/bisecting_k_means_example.py", line 46, in <module>
    model.save(sc, path)
AttributeError: 'BisectingKMeansModel' object has no attribute 'save'
```

**elementwise_product_example.py**

It calls `collect` from the vector.

```bash
./bin/spark-submit examples/src/main/python/mllib/elementwise_product_example.py
```

```
Traceback (most recent call last):
  File ".../spark/examples/src/main/python/mllib/elementwise_product_example.py", line 48, in <module>
    for each in transformedData2.collect():
  File ".../spark/python/pyspark/mllib/linalg/__init__.py", line 478, in __getattr__
    return getattr(self.array, item)
AttributeError: 'numpy.ndarray' object has no attribute 'collect'
```

**These three tests look throwing an exception for a relative path set in `spark.sql.warehouse.dir`.**

**hive.py**

```
./bin/spark-submit examples/src/main/python/sql/hive.py
```

```
Traceback (most recent call last):
  File ".../spark/examples/src/main/python/sql/hive.py", line 47, in <module>
    spark.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING) USING hive")
  File ".../spark/python/lib/pyspark.zip/pyspark/sql/session.py", line 541, in sql
  File ".../spark/python/lib/py4j-0.10.4-src.zip/py4j/java_gateway.py", line 1133, in __call__
  File ".../spark/python/lib/pyspark.zip/pyspark/sql/utils.py", line 69, in deco
pyspark.sql.utils.AnalysisException: 'org.apache.hadoop.hive.ql.metadata.HiveException: MetaException(message:java.lang.IllegalArgumentException: java.net.URISyntaxException: Relative path in absolute URI: file:./spark-warehouse);'
```

**SparkHiveExample.scala**

```
./bin/run-example sql.hive.SparkHiveExample
```

```
Exception in thread "main" org.apache.hadoop.hive.ql.metadata.HiveException: Unable to alter table. java.lang.IllegalArgumentException: java.net.URISyntaxException: Relative path in absolute URI: file:./spark-warehouse
	at org.apache.hadoop.hive.ql.metadata.Hive.alterTable(Hive.java:498)
	at org.apache.hadoop.hive.ql.metadata.Hive.alterTable(Hive.java:484)
	at org.apache.hadoop.hive.ql.metadata.Hive.loadTable(Hive.java:1668)
```

**JavaSparkHiveExample.java**

```
./bin/run-example sql.hive.JavaSparkHiveExample
```

```
Exception in thread "main" org.apache.hadoop.hive.ql.metadata.HiveException: Unable to alter table. java.lang.IllegalArgumentException: java.net.URISyntaxException: Relative path in absolute URI: file:./spark-warehouse
	at org.apache.hadoop.hive.ql.metadata.Hive.alterTable(Hive.java:498)
	at org.apache.hadoop.hive.ql.metadata.Hive.alterTable(Hive.java:484)
	at org.apache.hadoop.hive.ql.metadata.Hive.loadTable(Hive.java:1668)
```

## How was this patch tested?

Manually via

```
./bin/spark-submit examples/src/main/python/mllib/binary_classification_metrics_example.py
```

```
PYSPARK_PYTHON=python3 ./bin/spark-submit examples/src/main/python/status_api_demo.py
```

```
./bin/spark-submit examples/src/main/python/mllib/bisecting_k_means_example.py
```

```
./bin/spark-submit examples/src/main/python/mllib/elementwise_product_example.py
```

```
./bin/spark-submit examples/src/main/python/sql/hive.py
```

```
./bin/run-example sql.hive.JavaSparkHiveExample
```

```
./bin/run-example sql.hive.SparkHiveExample
```

These were found via

```bash
find ./examples/src/main/python -name "*.py" -exec spark-submit {} \;
```

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #16515 from HyukjinKwon/minor-example-fix.

## What changes were proposed in this pull request?

Today we have different syntax to create data source or hive serde tables, we should unify them to not confuse users and step forward to make hive a data source.

Please read https://issues.apache.org/jira/secure/attachment/12843835/CREATE-TABLE.pdf for  details.

TODO(for follow-up PRs):
1. TBLPROPERTIES is not added to the new syntax, we should decide if we wanna add it later.
2. `SHOW CREATE TABLE` should be updated to use the new syntax.
3. we should decide if we wanna change the behavior of `SET LOCATION`.

## How was this patch tested?

new tests

Author: Wenchen Fan <wenchen@databricks.com>

Closes #16296 from cloud-fan/create-table.

## What changes were proposed in this pull request?
There are many locations in the Spark repo where the same word occurs consecutively. Sometimes they are appropriately placed, but many times they are not. This PR removes the inappropriately duplicated words.

## How was this patch tested?
N/A since only docs or comments were updated.

Author: Niranjan Padmanabhan <niranjan.padmanabhan@gmail.com>

Closes #16455 from neurons/np.structure_streaming_doc.

## What changes were proposed in this pull request?

Add `finally` clause for `sc.stop()` in the `test("register and deregister Spark listener from SparkContext")`.

## How was this patch tested?
Pass the build and unit tests.

Author: Weiqing Yang <yangweiqing001@gmail.com>

Closes #16426 from weiqingy/testIssue.

## What changes were proposed in this pull request?

This PR proposes to check pep8 against all other Python scripts and fix the errors as below:

```bash
./dev/create-release/generate-contributors.py
./dev/create-release/releaseutils.py
./dev/create-release/translate-contributors.py
./dev/lint-python
./python/docs/epytext.py
./examples/src/main/python/mllib/decision_tree_classification_example.py
./examples/src/main/python/mllib/decision_tree_regression_example.py
./examples/src/main/python/mllib/gradient_boosting_classification_example.py
./examples/src/main/python/mllib/gradient_boosting_regression_example.py
./examples/src/main/python/mllib/linear_regression_with_sgd_example.py
./examples/src/main/python/mllib/logistic_regression_with_lbfgs_example.py
./examples/src/main/python/mllib/naive_bayes_example.py
./examples/src/main/python/mllib/random_forest_classification_example.py
./examples/src/main/python/mllib/random_forest_regression_example.py
./examples/src/main/python/mllib/svm_with_sgd_example.py
./examples/src/main/python/streaming/network_wordjoinsentiments.py
./sql/hive/src/test/resources/data/scripts/cat.py
./sql/hive/src/test/resources/data/scripts/cat_error.py
./sql/hive/src/test/resources/data/scripts/doubleescapedtab.py
./sql/hive/src/test/resources/data/scripts/dumpdata_script.py
./sql/hive/src/test/resources/data/scripts/escapedcarriagereturn.py
./sql/hive/src/test/resources/data/scripts/escapednewline.py
./sql/hive/src/test/resources/data/scripts/escapedtab.py
./sql/hive/src/test/resources/data/scripts/input20_script.py
./sql/hive/src/test/resources/data/scripts/newline.py
```

## How was this patch tested?

- `./python/docs/epytext.py`

  ```bash
  cd ./python/docs $$ make html
  ```

- pep8 check (Python 2.7 / Python 3.3.6)

  ```
  ./dev/lint-python
  ```

- `./dev/merge_spark_pr.py` (Python 2.7 only / Python 3.3.6 not working)

  ```bash
  python -m doctest -v ./dev/merge_spark_pr.py
  ```

- `./dev/create-release/releaseutils.py` `./dev/create-release/generate-contributors.py` `./dev/create-release/translate-contributors.py` (Python 2.7 only / Python 3.3.6 not working)

  ```bash
  python generate-contributors.py
  python translate-contributors.py
  ```

- Examples (Python 2.7 / Python 3.3.6)

  ```bash
  ./bin/spark-submit examples/src/main/python/mllib/decision_tree_classification_example.py
  ./bin/spark-submit examples/src/main/python/mllib/decision_tree_regression_example.py
  ./bin/spark-submit examples/src/main/python/mllib/gradient_boosting_classification_example.py
  ./bin/spark-submit examples/src/main/python/mllib/gradient_boosting_regression_example.p
  ./bin/spark-submit examples/src/main/python/mllib/random_forest_classification_example.py
  ./bin/spark-submit examples/src/main/python/mllib/random_forest_regression_example.py
  ```

- Examples (Python 2.7 only / Python 3.3.6 not working)
  ```
  ./bin/spark-submit examples/src/main/python/mllib/linear_regression_with_sgd_example.py
  ./bin/spark-submit examples/src/main/python/mllib/logistic_regression_with_lbfgs_example.py
  ./bin/spark-submit examples/src/main/python/mllib/naive_bayes_example.py
  ./bin/spark-submit examples/src/main/python/mllib/svm_with_sgd_example.py
  ```

- `sql/hive/src/test/resources/data/scripts/*.py` (Python 2.7 / Python 3.3.6 within suggested changes)

  Manually tested only changed ones.

- `./dev/github_jira_sync.py` (Python 2.7 only / Python 3.3.6 not working)

  Manually tested this after disabling actually adding comments and links.

And also via Jenkins tests.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #16405 from HyukjinKwon/minor-pep8.

## What changes were proposed in this pull request?
* Add all R examples for ML wrappers which were added during 2.1 release cycle.
* Split the whole ```ml.R``` example file into individual example for each algorithm, which will be convenient for users to rerun them.
* Add corresponding examples to ML user guide.
* Update ML section of SparkR user guide.

Note: MLlib Scala/Java/Python examples will be consistent, however, SparkR examples may different from them, since R users may use the algorithms in a different way, for example, using R ```formula``` to specify ```featuresCol``` and ```labelCol```.

## How was this patch tested?
Run all examples manually.

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #16148 from yanboliang/spark-18325.

## What changes were proposed in this pull request?
Logistic Regression summary is added in Python API. We need to add example and document for summary.

The newly added example is consistent with Scala and Java examples.

## How was this patch tested?

Manually tests: Run the example with spark-submit; copy & paste code into pyspark; build document and check the document.

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #16064 from wangmiao1981/py.

## What changes were proposed in this pull request?
The user guide for LSH is added to ml-features.md, with several scala/java examples in spark-examples.

## How was this patch tested?
Doc has been generated through Jekyll, and checked through manual inspection.

Author: Yunni <Euler57721@gmail.com>
Author: Yun Ni <yunn@uber.com>
Author: Joseph K. Bradley <joseph@databricks.com>
Author: Yun Ni <Euler57721@gmail.com>

Closes #15795 from Yunni/SPARK-18081-lsh-guide.

## What changes were proposed in this pull request?
This patch bumps master branch version to 2.2.0-SNAPSHOT.

## How was this patch tested?
N/A

Author: Reynold Xin <rxin@databricks.com>

Closes #16126 from rxin/SPARK-18695.

## What changes were proposed in this pull request?

Small fix, fix the errors caused by lint check in Java

- Clear unused objects and `UnusedImports`.
- Add comments around the method `finalize` of `NioBufferedFileInputStream`to turn off checkstyle.
- Cut the line which is longer than 100 characters into two lines.

## How was this patch tested?
Travis CI.
```
$ build/mvn -T 4 -q -DskipTests -Pyarn -Phadoop-2.3 -Pkinesis-asl -Phive -Phive-thriftserver install
$ dev/lint-java
```
Before:
```
Checkstyle checks failed at following occurrences:
[ERROR] src/main/java/org/apache/spark/network/util/TransportConf.java:[21,8] (imports) UnusedImports: Unused import - org.apache.commons.crypto.cipher.CryptoCipherFactory.
[ERROR] src/test/java/org/apache/spark/network/sasl/SparkSaslSuite.java:[516,5] (modifier) RedundantModifier: Redundant 'public' modifier.
[ERROR] src/main/java/org/apache/spark/io/NioBufferedFileInputStream.java:[133] (coding) NoFinalizer: Avoid using finalizer method.
[ERROR] src/main/java/org/apache/spark/sql/catalyst/expressions/UnsafeMapData.java:[71] (sizes) LineLength: Line is longer than 100 characters (found 113).
[ERROR] src/main/java/org/apache/spark/sql/catalyst/expressions/UnsafeArrayData.java:[112] (sizes) LineLength: Line is longer than 100 characters (found 110).
[ERROR] src/test/java/org/apache/spark/sql/catalyst/expressions/HiveHasherSuite.java:[31,17] (modifier) ModifierOrder: 'static' modifier out of order with the JLS suggestions.
[ERROR]src/main/java/org/apache/spark/examples/ml/JavaLogisticRegressionWithElasticNetExample.java:[64] (sizes) LineLength: Line is longer than 100 characters (found 103).
[ERROR] src/main/java/org/apache/spark/examples/ml/JavaInteractionExample.java:[22,8] (imports) UnusedImports: Unused import - org.apache.spark.ml.linalg.Vectors.
[ERROR] src/main/java/org/apache/spark/examples/ml/JavaInteractionExample.java:[51] (regexp) RegexpSingleline: No trailing whitespace allowed.
```

After:
```
$ build/mvn -T 4 -q -DskipTests -Pyarn -Phadoop-2.3 -Pkinesis-asl -Phive -Phive-thriftserver install
$ dev/lint-java
Using `mvn` from path: /home/travis/build/ConeyLiu/spark/build/apache-maven-3.3.9/bin/mvn
Checkstyle checks passed.
```

Author: Xianyang Liu <xyliu0530@icloud.com>

Closes #15865 from ConeyLiu/master.

## What changes were proposed in this pull request?

This PR provides structured kafka wordcount examples

## How was this patch tested?

Author: uncleGen <hustyugm@gmail.com>

Closes #15849 from uncleGen/SPARK-18410.

## What changes were proposed in this pull request?
1,Remove `runs` from docs of mllib.KMeans
2,Add notes for `k` according to comments in sources
## How was this patch tested?
existing tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #15873 from zhengruifeng/update_doc_mllib_kmeans.

## What changes were proposed in this pull request?

This is a follow-up work of #15618.

Close file source;
For any newly created streaming context outside the withContext, explicitly close the context.

## How was this patch tested?

Existing unit tests.

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #15818 from wangmiao1981/rtest.

I created Scala and Java example and added documentation.

Author: chie8842 <hayashidac@nttdata.co.jp>

Closes #15658 from hayashidac/SPARK-13770.

## What changes were proposed in this pull request?

If my understanding is correct we should be rather looking at closed disk than the opened one.
## How was this patch tested?

Run simple comparison, of the mean squared error of approaches with closed and opened disk.
https://gist.github.com/mrydzy/1cf0e5c316ef9d6fbd91426b91f1969f
The closed one performed slightly better, but the tested sample wasn't too big, so I rely mostly on the algorithm  understanding.

Author: Maria Rydzy <majrydzy+gh@gmail.com>

Closes #15687 from mrydzy/master.

## What changes were proposed in this pull request?

In Python 3, there is only one integer type (i.e., int), which mostly behaves like the long type in Python 2. Since Python 3 won't accept "L", so removed "L" in all examples.

## How was this patch tested?

Unit tests.

…rrors]

Author: Jagadeesan <as2@us.ibm.com>

Closes #15660 from jagadeesanas2/SPARK-18133.

## What changes were proposed in this pull request?

https://issues.apache.org/jira/browse/SPARK-14300

Duplicated code found in scala/examples/mllib, below all deleted in this PR:

- DenseGaussianMixture.scala
- StreamingLinearRegression.scala

## delete reasons:

#### delete: mllib/DenseGaussianMixture.scala

- duplicate of mllib/GaussianMixtureExample

#### delete: mllib/StreamingLinearRegression.scala

- duplicate of mllib/StreamingLinearRegressionExample

When merging and cleaning those code, be sure not disturb the previous example on and off blocks.

## How was this patch tested?

Test with `SKIP_API=1 jekyll` manually to make sure that works well.

Author: Xin Ren <iamshrek@126.com>

Closes #12195 from keypointt/SPARK-14300.

[SPARK-17810][SQL] Default spark.sql.warehouse.dir is relative to local FS but can resolve as HDFS path

## What changes were proposed in this pull request?

Always resolve spark.sql.warehouse.dir as a local path, and as relative to working dir not home dir

## How was this patch tested?

Existing tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #15382 from srowen/SPARK-17810.

## What changes were proposed in this pull request?

The python example for tf_idf with the parameter "minDocFreq" is not properly set up because the same variable is used to transform the document for both with and without the "minDocFreq" parameter.
The IDF(minDocFreq=2) is stored in the variable "idfIgnore" but then it is the original variable "idf" used to transform the "tf" instead of the "idfIgnore".

## How was this patch tested?

Before the results for "tfidf" and "tfidfIgnore" were the same:
tfidf:
(1048576,[1046921],[3.75828890549])
(1048576,[1046920],[3.75828890549])
(1048576,[1046923],[3.75828890549])
(1048576,[892732],[3.75828890549])
(1048576,[892733],[3.75828890549])
(1048576,[892734],[3.75828890549])
tfidfIgnore:
(1048576,[1046921],[3.75828890549])
(1048576,[1046920],[3.75828890549])
(1048576,[1046923],[3.75828890549])
(1048576,[892732],[3.75828890549])
(1048576,[892733],[3.75828890549])
(1048576,[892734],[3.75828890549])

After the fix those are how they should be:
tfidf:
(1048576,[1046921],[3.75828890549])
(1048576,[1046920],[3.75828890549])
(1048576,[1046923],[3.75828890549])
(1048576,[892732],[3.75828890549])
(1048576,[892733],[3.75828890549])
(1048576,[892734],[3.75828890549])
tfidfIgnore:
(1048576,[1046921],[0.0])
(1048576,[1046920],[0.0])
(1048576,[1046923],[0.0])
(1048576,[892732],[0.0])
(1048576,[892733],[0.0])
(1048576,[892734],[0.0])

Author: Maxime Rihouey <maxime.rihouey@gmail.com>

Closes #15503 from maximerihouey/patch-1.

## What changes were proposed in this pull request?

Global temporary view is a cross-session temporary view, which means it's shared among all sessions. Its lifetime is the lifetime of the Spark application, i.e. it will be automatically dropped when the application terminates. It's tied to a system preserved database `global_temp`(configurable via SparkConf), and we must use the qualified name to refer a global temp view, e.g. SELECT * FROM global_temp.view1.

changes for `SessionCatalog`:

1. add a new field `gloabalTempViews: GlobalTempViewManager`, to access the shared global temp views, and the global temp db name.
2. `createDatabase` will fail if users wanna create `global_temp`, which is system preserved.
3. `setCurrentDatabase` will fail if users wanna set `global_temp`, which is system preserved.
4. add `createGlobalTempView`, which is used in `CreateViewCommand` to create global temp views.
5. add `dropGlobalTempView`, which is used in `CatalogImpl` to drop global temp view.
6. add `alterTempViewDefinition`, which is used in `AlterViewAsCommand` to update the view definition for local/global temp views.
7. `renameTable`/`dropTable`/`isTemporaryTable`/`lookupRelation`/`getTempViewOrPermanentTableMetadata`/`refreshTable` will handle global temp views.

changes for SQL commands:

1. `CreateViewCommand`/`AlterViewAsCommand` is updated to support global temp views
2. `ShowTablesCommand` outputs a new column `database`, which is used to distinguish global and local temp views.
3. other commands can also handle global temp views if they call `SessionCatalog` APIs which accepts global temp views, e.g. `DropTableCommand`, `AlterTableRenameCommand`, `ShowColumnsCommand`, etc.

changes for other public API

1. add a new method `dropGlobalTempView` in `Catalog`
2. `Catalog.findTable` can find global temp view
3. add a new method `createGlobalTempView` in `Dataset`

## How was this patch tested?

new tests in `SQLViewSuite`

Author: Wenchen Fan <wenchen@databricks.com>

Closes #14897 from cloud-fan/global-temp-view.

## What changes were proposed in this pull request?
Updates user guide to reflect that LogisticRegression now supports multiclass. Also adds new examples to show multiclass training.

## How was this patch tested?
Ran locally using spark-submit, run-example, and copy/paste from user guide into shells. Generated docs and verified correct output.

Author: sethah <seth.hendrickson16@gmail.com>

Closes #15349 from sethah/SPARK-17239.

## What changes were proposed in this pull request?

This change modifies the implementation of DataFrameWriter.save such that it works with jdbc, and the call to jdbc merely delegates to save.

## How was this patch tested?

This was tested via unit tests in the JDBCWriteSuite, of which I added one new test to cover this scenario.

## Additional details

rxin This seems to have been most recently touched by you and was also commented on in the JIRA.

This contribution is my original work and I license the work to the project under the project's open source license.

Author: Justin Pihony <justin.pihony@gmail.com>
Author: Justin Pihony <justin.pihony@typesafe.com>

Closes #12601 from JustinPihony/jdbc_reconciliation.

Code is equivalent, but map comprehency is most of the time faster than a map.

Author: Gaetan Semet <gaetan@xeberon.net>

Closes #14863 from Stibbons/map_comprehension.

## What changes were proposed in this pull request?

We propose to fix the Encoder type in the Dataset example

## How was this patch tested?

The PR will be tested with the current unit test cases

Author: CodingCat <zhunansjtu@gmail.com>

Closes #14901 from CodingCat/SPARK-17347.

## What changes were proposed in this pull request?

Allow centering / mean scaling of sparse vectors in StandardScaler, if requested. This is for compatibility with `VectorAssembler` in common usages.

## How was this patch tested?

Jenkins tests, including new caes to reflect the new behavior.

Author: Sean Owen <sowen@cloudera.com>

Closes #14663 from srowen/SPARK-17001.

## What changes were proposed in this pull request?
As Spark 2.0.1 will be released soon (mentioned in the spark dev mailing list), besides the critical bugs, it's better to fix the code style errors before the release.

Before:
```
./dev/lint-java
Checkstyle checks failed at following occurrences:
[ERROR] src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java:[525] (sizes) LineLength: Line is longer than 100 characters (found 119).
[ERROR] src/main/java/org/apache/spark/examples/sql/streaming/JavaStructuredNetworkWordCount.java:[64] (sizes) LineLength: Line is longer than 100 characters (found 103).
```
After:
```
./dev/lint-java
Using `mvn` from path: /usr/local/bin/mvn
Checkstyle checks passed.
```
## How was this patch tested?
Manual.

Author: Weiqing Yang <yangweiqing001@gmail.com>

Closes #14768 from Sherry302/fixjavastyle.

## What changes were proposed in this pull request?

(Please fill in changes proposed in this fix)

For R SQL example, appname is "MyApp". While examples in scala, Java and python, the appName is "x Spark SQL basic example".

I made the R example consistent with other examples.

## How was this patch tested?

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)

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

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #14703 from wangmiao1981/example.

## What changes were proposed in this pull request?

Originally this PR was based on #14491 but I realised that fixing examples are more sensible rather than comments.

This PR fixes three things below:

 - Fix two wrong examples in `structured-streaming-programming-guide.md`. Loading via `read.load(..)` without `as` will be `Dataset<Row>` not `Dataset<String>` in Java.

- Fix indentation across `structured-streaming-programming-guide.md`. Python has 4 spaces and Scala and Java have double spaces. These are inconsistent across the examples.

- Fix `StructuredNetworkWordCountWindowed` and  `StructuredNetworkWordCount` in Java and Scala to initially load `DataFrame` and `Dataset<Row>` to be consistent with the comments and some examples in `structured-streaming-programming-guide.md` and to match Scala and Java to Python one (Python one loads it as `DataFrame` initially).

## How was this patch tested?

N/A

Closes https://github.com/apache/spark/pull/14491

Author: hyukjinkwon <gurwls223@gmail.com>
Author: Ganesh Chand <ganeshchand@Ganeshs-MacBook-Pro-2.local>

Closes #14564 from HyukjinKwon/SPARK-16886.

## What changes were proposed in this pull request?
This PR is to fix the minor Java linter errors as following:
[ERROR] src/main/java/org/apache/spark/sql/catalyst/expressions/VariableLengthRowBasedKeyValueBatch.java:[42,10] (modifier) RedundantModifier: Redundant 'final' modifier.
[ERROR] src/main/java/org/apache/spark/sql/catalyst/expressions/VariableLengthRowBasedKeyValueBatch.java:[97,10] (modifier) RedundantModifier: Redundant 'final' modifier.

## How was this patch tested?
Manual test.
dev/lint-java
Using `mvn` from path: /usr/local/bin/mvn
Checkstyle checks passed.

Author: Weiqing Yang <yangweiqing001@gmail.com>

Closes #14532 from Sherry302/master.

## What changes were proposed in this pull request?
Improve example outputs to better reflect the functionality that is being presented.  This mostly consisted of modifying what was printed at the end of the example, such as calling show() with truncate=False, but sometimes required minor tweaks in the example data to get relevant output.  Explicitly set parameters when they are used as part of the example.  Fixed Java examples that failed to run because of using old-style MLlib Vectors or problem with schema.  Synced examples between different APIs.

## How was this patch tested?
Ran each example for Scala, Python, and Java and made sure output was legible on a terminal of width 100.

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #14308 from BryanCutler/ml-examples-improve-output-SPARK-16260.

## What changes were proposed in this pull request?

Modify java example which is also reflect in document.

## How was this patch tested?

run test cases.

Author: sandy <phalodi@gmail.com>

Closes #14436 from phalodi/SPARK-16816.

[SPARK-16558][EXAMPLES][MLLIB] examples/mllib/LDAExample should use MLVector instead of MLlib Vector

## What changes were proposed in this pull request?

mllib.LDAExample uses ML pipeline and MLlib LDA algorithm. The former transforms original data into MLVector format, while the latter uses MLlibVector format.

## How was this patch tested?

Test manually.

Author: Xusen Yin <yinxusen@gmail.com>

Closes #14212 from yinxusen/SPARK-16558.

## What changes were proposed in this pull request?

This PR makes various minor updates to examples of all language bindings to make sure they are consistent with each other. Some typos and missing parts (JDBC example in Scala/Java/Python) are also fixed.

## How was this patch tested?

Manually tested.

Author: Cheng Lian <lian@databricks.com>

Closes #14368 from liancheng/revise-examples.

## What changes were proposed in this pull request?
Some Java examples are using mllib.linalg.Vectors instead of ml.linalg.Vectors and causes an exception when run.  Also there are some Java examples that incorrectly specify data types in the schema, also causing an exception.

## How was this patch tested?
Ran corrected examples locally

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #14405 from BryanCutler/java-examples-ml.Vectors-fix-SPARK-16800.

[SPARK-16694][CORE] Use for/foreach rather than map for Unit expressions whose side effects are required

## What changes were proposed in this pull request?

Use foreach/for instead of map where operation requires execution of body, not actually defining a transformation

## How was this patch tested?

Jenkins

Author: Sean Owen <sowen@cloudera.com>

Closes #14332 from srowen/SPARK-16694.

This PR is based on PR #14098 authored by wangmiao1981.

## What changes were proposed in this pull request?

This PR replaces the original Python Spark SQL example file with the following three files:

- `sql/basic.py`

  Demonstrates basic Spark SQL features.

- `sql/datasource.py`

  Demonstrates various Spark SQL data sources.

- `sql/hive.py`

  Demonstrates Spark SQL Hive interaction.

This PR also removes hard-coded Python example snippets in the SQL programming guide by extracting snippets from the above files using the `include_example` Liquid template tag.

## How was this patch tested?

Manually tested.

Author: wm624@hotmail.com <wm624@hotmail.com>
Author: Cheng Lian <lian@databricks.com>

Closes #14317 from liancheng/py-examples-update.

[SPARK-16535][BUILD] In pom.xml, remove groupId which is redundant definition and inherited from the parent

https://issues.apache.org/jira/browse/SPARK-16535

## What changes were proposed in this pull request?

When I scan through the pom.xml of sub projects, I found this warning as below and attached screenshot
```
Definition of groupId is redundant, because it's inherited from the parent
```
![screen shot 2016-07-13 at 3 13 11 pm](https://cloud.githubusercontent.com/assets/3925641/16823121/744f893e-4916-11e6-8a52-042f83b9db4e.png)

I've tried to remove some of the lines with groupId definition, and the build on my local machine is still ok.
```
<groupId>org.apache.spark</groupId>
```
As I just find now `<maven.version>3.3.9</maven.version>` is being used in Spark 2.x, and Maven-3 supports versionless parent elements: Maven 3 will remove the need to specify the parent version in sub modules. THIS is great (in Maven 3.1).

ref: http://stackoverflow.com/questions/3157240/maven-3-worth-it/3166762#3166762

## How was this patch tested?

I've tested by re-building the project, and build succeeded.

Author: Xin Ren <iamshrek@126.com>

Closes #14189 from keypointt/SPARK-16535.