## What changes were proposed in this pull request?

REPL module depends on SQL module, so we should run REPL tests if SQL module has code changes.

## How was this patch tested?

N/A

Author: Wenchen Fan <wenchen@databricks.com>

Closes #18191 from cloud-fan/test.

## What changes were proposed in this pull request?

This PR proposes two things as below:

- Avoid Unidoc build only if Hadoop 2.6 is explicitly set in SBT build

  Due to a different dependency resolution in SBT & Unidoc by an unknown reason, the documentation build fails on a specific machine & environment in Jenkins but it was unable to reproduce.

  So, this PR just checks an environment variable `AMPLAB_JENKINS_BUILD_PROFILE` that is set in Hadoop 2.6 SBT build against branches on Jenkins, and then disables Unidoc build. **Note that PR builder will still build it with Hadoop 2.6 & SBT.**

  ```
  ========================================================================
  Building Unidoc API Documentation
  ========================================================================
  [info] Building Spark unidoc (w/Hive 1.2.1) using SBT with these arguments:  -Phadoop-2.6 -Pmesos -Pkinesis-asl -Pyarn -Phive-thriftserver -Phive unidoc
  Using /usr/java/jdk1.8.0_60 as default JAVA_HOME.
  ...
  ```

  I checked the environment variables from the logs (first bit) as below:

  - **spark-master-test-sbt-hadoop-2.6** (this one is being failed) - https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.6/lastBuild/consoleFull

  ```
  JAVA_HOME=/usr/java/jdk1.8.0_60
  JAVA_7_HOME=/usr/java/jdk1.7.0_79
  SPARK_BRANCH=master
  AMPLAB_JENKINS_BUILD_PROFILE=hadoop2.6   <- I use this variable
  AMPLAB_JENKINS="true"
  ```
  - spark-master-test-sbt-hadoop-2.7 - https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.7/lastBuild/consoleFull

  ```
  JAVA_HOME=/usr/java/jdk1.8.0_60
  JAVA_7_HOME=/usr/java/jdk1.7.0_79
  SPARK_BRANCH=master
  AMPLAB_JENKINS_BUILD_PROFILE=hadoop2.7
  AMPLAB_JENKINS="true"
  ```

  - spark-master-test-maven-hadoop-2.6 - https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-maven-hadoop-2.6/lastBuild/consoleFull

  ```
  JAVA_HOME=/usr/java/jdk1.8.0_60
  JAVA_7_HOME=/usr/java/jdk1.7.0_79
  HADOOP_PROFILE=hadoop-2.6
  HADOOP_VERSION=
  SPARK_BRANCH=master
  AMPLAB_JENKINS="true"
  ```

  - spark-master-test-maven-hadoop-2.7 - https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-maven-hadoop-2.7/lastBuild/consoleFull

  ```
  JAVA_HOME=/usr/java/jdk1.8.0_60
  JAVA_7_HOME=/usr/java/jdk1.7.0_79
  HADOOP_PROFILE=hadoop-2.7
  HADOOP_VERSION=
  SPARK_BRANCH=master
  AMPLAB_JENKINS="true"
  ```

  - PR builder - https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/75843/consoleFull

  ```
  JENKINS_MASTER_HOSTNAME=amp-jenkins-master
  JAVA_HOME=/usr/java/jdk1.8.0_60
  JAVA_7_HOME=/usr/java/jdk1.7.0_79
  ```

  Assuming from other logs in branch-2.1

    - SBT & Hadoop 2.6 against branch-2.1 https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-branch-2.1-test-sbt-hadoop-2.6/lastBuild/consoleFull

      ```
      JAVA_HOME=/usr/java/jdk1.8.0_60
      JAVA_7_HOME=/usr/java/jdk1.7.0_79
      SPARK_BRANCH=branch-2.1
      AMPLAB_JENKINS_BUILD_PROFILE=hadoop2.6
      AMPLAB_JENKINS="true"
      ```

    - Maven & Hadoop 2.6 against branch-2.1 https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-branch-2.1-test-maven-hadoop-2.6/lastBuild/consoleFull

      ```
      JAVA_HOME=/usr/java/jdk1.8.0_60
      JAVA_7_HOME=/usr/java/jdk1.7.0_79
      HADOOP_PROFILE=hadoop-2.6
      HADOOP_VERSION=
      SPARK_BRANCH=branch-2.1
      AMPLAB_JENKINS="true"
      ```

  We have been using the same convention for those variables. These are actually being used in `run-tests.py` script - here https://github.com/apache/spark/blob/master/dev/run-tests.py#L519-L520

- Revert the previous try

  After https://github.com/apache/spark/pull/17651, it seems the build still fails on SBT Hadoop 2.6 master.

  I am unable to reproduce this - https://github.com/apache/spark/pull/17477#issuecomment-294094092 and the reviewer was too. So, this got merged as it looks the only way to verify this is to merge it currently (as no one seems able to reproduce this).

## How was this patch tested?

I only checked `is_hadoop_version_2_6 = os.environ.get("AMPLAB_JENKINS_BUILD_PROFILE") == "hadoop2.6"` is working fine as expected as below:

```python
>>> import collections
>>> os = collections.namedtuple('os', 'environ')(environ={"AMPLAB_JENKINS_BUILD_PROFILE": "hadoop2.6"})
>>> print(not os.environ.get("AMPLAB_JENKINS_BUILD_PROFILE") == "hadoop2.6")
False
>>> os = collections.namedtuple('os', 'environ')(environ={"AMPLAB_JENKINS_BUILD_PROFILE": "hadoop2.7"})
>>> print(not os.environ.get("AMPLAB_JENKINS_BUILD_PROFILE") == "hadoop2.6")
True
>>> os = collections.namedtuple('os', 'environ')(environ={})
>>> print(not os.environ.get("AMPLAB_JENKINS_BUILD_PROFILE") == "hadoop2.6")
True
```

I tried many ways but I was unable to reproduce this in my local. Sean also tried the way I did but he was also unable to reproduce this.

Please refer the comments in https://github.com/apache/spark/pull/17477#issuecomment-294094092

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #17669 from HyukjinKwon/revert-SPARK-20343.

## What changes were proposed in this pull request?

This PR proposes to run Spark unidoc to test Javadoc 8 build as Javadoc 8 is easily re-breakable.

There are several problems with it:

- It introduces little extra bit of time to run the tests. In my case, it took 1.5 mins more (`Elapsed :[94.8746569157]`). How it was tested is described in "How was this patch tested?".

- > One problem that I noticed was that Unidoc appeared to be processing test sources: if we can find a way to exclude those from being processed in the first place then that might significantly speed things up.

  (see  joshrosen's [comment](https://issues.apache.org/jira/browse/SPARK-18692?focusedCommentId=15947627&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15947627))

To complete this automated build, It also suggests to fix existing Javadoc breaks / ones introduced by test codes as described above.

There fixes are similar instances that previously fixed. Please refer https://github.com/apache/spark/pull/15999 and https://github.com/apache/spark/pull/16013

Note that this only fixes **errors** not **warnings**. Please see my observation https://github.com/apache/spark/pull/17389#issuecomment-288438704 for spurious errors by warnings.

## How was this patch tested?

Manually via `jekyll build` for building tests. Also, tested via running `./dev/run-tests`.

This was tested via manually adding `time.time()` as below:

```diff
     profiles_and_goals = build_profiles + sbt_goals

     print("[info] Building Spark unidoc (w/Hive 1.2.1) using SBT with these arguments: ",
           " ".join(profiles_and_goals))

+    import time
+    st = time.time()
     exec_sbt(profiles_and_goals)
+    print("Elapsed :[%s]" % str(time.time() - st))
```

produces

```
...
========================================================================
Building Unidoc API Documentation
========================================================================
...
[info] Main Java API documentation successful.
...
Elapsed :[94.8746569157]
...

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #17477 from HyukjinKwon/SPARK-18692.

- Move external/java8-tests tests into core, streaming, sql and remove
- Remove MaxPermGen and related options
- Fix some reflection / TODOs around Java 8+ methods
- Update doc references to 1.7/1.8 differences
- Remove Java 7/8 related build profiles
- Update some plugins for better Java 8 compatibility
- Fix a few Java-related warnings

For the future:

- Update Java 8 examples to fully use Java 8
- Update Java tests to use lambdas for simplicity
- Update Java internal implementations to use lambdas

## How was this patch tested?

Existing tests

Author: Sean Owen <sowen@cloudera.com>

Closes #16871 from srowen/SPARK-19493.

## What changes were proposed in this pull request?

After SPARK-19464, **SparkPullRequestBuilder** fails because it still tries to use hadoop2.3.

**BEFORE**
https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/72595/console
```
========================================================================
Building Spark
========================================================================
[error] Could not find hadoop2.3 in the list. Valid options  are ['hadoop2.6', 'hadoop2.7']
Attempting to post to Github...
 > Post successful.
```

**AFTER**
https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/72595/console
```
========================================================================
Building Spark
========================================================================
[info] Building Spark (w/Hive 1.2.1) using SBT with these arguments:  -Phadoop-2.6 -Pmesos -Pkinesis-asl -Pyarn -Phive-thriftserver -Phive test:package streaming-kafka-0-8-assembly/assembly streaming-flume-assembly/assembly streaming-kinesis-asl-assembly/assembly
Using /usr/java/jdk1.8.0_60 as default JAVA_HOME.
Note, this will be overridden by -java-home if it is set.
```

## How was this patch tested?

Pass the existing test.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #16858 from dongjoon-hyun/hotfix_run-tests.

## What changes were proposed in this pull request?

- Remove support for Hadoop 2.5 and earlier
- Remove reflection and code constructs only needed to support multiple versions at once
- Update docs to reflect newer versions
- Remove older versions' builds and profiles.

## How was this patch tested?

Existing tests

Author: Sean Owen <sowen@cloudera.com>

Closes #16810 from srowen/SPARK-19464.

## What changes were proposed in this pull request?

This PR aims to provide a pip installable PySpark package. This does a bunch of work to copy the jars over and package them with the Python code (to prevent challenges from trying to use different versions of the Python code with different versions of the JAR). It does not currently publish to PyPI but that is the natural follow up (SPARK-18129).

Done:
- pip installable on conda [manual tested]
- setup.py installed on a non-pip managed system (RHEL) with YARN [manual tested]
- Automated testing of this (virtualenv)
- packaging and signing with release-build*

Possible follow up work:
- release-build update to publish to PyPI (SPARK-18128)
- figure out who owns the pyspark package name on prod PyPI (is it someone with in the project or should we ask PyPI or should we choose a different name to publish with like ApachePySpark?)
- Windows support and or testing ( SPARK-18136 )
- investigate details of wheel caching and see if we can avoid cleaning the wheel cache during our test
- consider how we want to number our dev/snapshot versions

Explicitly out of scope:
- Using pip installed PySpark to start a standalone cluster
- Using pip installed PySpark for non-Python Spark programs

*I've done some work to test release-build locally but as a non-committer I've just done local testing.
## How was this patch tested?

Automated testing with virtualenv, manual testing with conda, a system wide install, and YARN integration.

release-build changes tested locally as a non-committer (no testing of upload artifacts to Apache staging websites)

Author: Holden Karau <holden@us.ibm.com>
Author: Juliet Hougland <juliet@cloudera.com>
Author: Juliet Hougland <not@myemail.com>

Closes #15659 from holdenk/SPARK-1267-pip-install-pyspark.

## What changes were proposed in this pull request?

This PR adds a new project ` external/kafka-0-10-sql` for Structured Streaming Kafka source.

It's based on the design doc: https://docs.google.com/document/d/19t2rWe51x7tq2e5AOfrsM9qb8_m7BRuv9fel9i0PqR8/edit?usp=sharing

tdas did most of work and part of them was inspired by koeninger's work.

### Introduction

The Kafka source is a structured streaming data source to poll data from Kafka. The schema of reading data is as follows:

Column | Type
---- | ----
key | binary
value | binary
topic | string
partition | int
offset | long
timestamp | long
timestampType | int

The source can deal with deleting topics. However, the user should make sure there is no Spark job processing the data when deleting a topic.

### Configuration

The user can use `DataStreamReader.option` to set the following configurations.

Kafka Source's options | value | default | meaning
------ | ------- | ------ | -----
startingOffset | ["earliest", "latest"] | "latest" | The start point when a query is started, either "earliest" which is from the earliest offset, or "latest" which is just from the latest offset. Note: This only applies when a new Streaming query is started, and that resuming will always pick up from where the query left off.
failOnDataLost | [true, false] | true | Whether to fail the query when it's possible that data is lost (e.g., topics are deleted, or offsets are out of range). This may be a false alarm. You can disable it when it doesn't work as you expected.
subscribe | A comma-separated list of topics | (none) | The topic list to subscribe. Only one of "subscribe" and "subscribeParttern" options can be specified for Kafka source.
subscribePattern | Java regex string | (none) | The pattern used to subscribe the topic. Only one of "subscribe" and "subscribeParttern" options can be specified for Kafka source.
kafka.consumer.poll.timeoutMs | long | 512 | The timeout in milliseconds to poll data from Kafka in executors
fetchOffset.numRetries | int | 3 | Number of times to retry before giving up fatch Kafka latest offsets.
fetchOffset.retryIntervalMs | long | 10 | milliseconds to wait before retrying to fetch Kafka offsets

Kafka's own configurations can be set via `DataStreamReader.option` with `kafka.` prefix, e.g, `stream.option("kafka.bootstrap.servers", "host:port")`

### Usage

* Subscribe to 1 topic
```Scala
spark
  .readStream
  .format("kafka")
  .option("kafka.bootstrap.servers", "host:port")
  .option("subscribe", "topic1")
  .load()
```

* Subscribe to multiple topics
```Scala
spark
  .readStream
  .format("kafka")
  .option("kafka.bootstrap.servers", "host:port")
  .option("subscribe", "topic1,topic2")
  .load()
```

* Subscribe to a pattern
```Scala
spark
  .readStream
  .format("kafka")
  .option("kafka.bootstrap.servers", "host:port")
  .option("subscribePattern", "topic.*")
  .load()
```

## How was this patch tested?

The new unit tests.

Author: Shixiong Zhu <shixiong@databricks.com>
Author: Tathagata Das <tathagata.das1565@gmail.com>
Author: Shixiong Zhu <zsxwing@gmail.com>
Author: cody koeninger <cody@koeninger.org>

Closes #15102 from zsxwing/kafka-source.

## What changes were proposed in this pull request?

Only build PRs with -Pyarn if YARN code was modified.

## How was this patch tested?

Jenkins tests (will look to verify whether -Pyarn was included in the PR builder for this one.)

Author: Sean Owen <sowen@cloudera.com>

Closes #14892 from srowen/SPARK-17329.

In the `dev/run-tests.py` script we check a `Popen.retcode` for success using `retcode > 0`, but this is subtlety wrong because Popen's return code will be negative if the child process was terminated by a signal: https://docs.python.org/2/library/subprocess.html#subprocess.Popen.returncode

In order to properly handle signals, we should change this to check `retcode != 0` instead.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #13692 from JoshRosen/dev-run-tests-return-code-handling.

## What changes were proposed in this pull request?

A follow up PR for #13655 to fix a wrong format tag.

## How was this patch tested?

Jenkins unit tests.

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #13665 from zsxwing/fix.

## What changes were proposed in this pull request?
I initially asked to create a hivecontext-compatibility module to put the HiveContext there. But we are so close to Spark 2.0 release and there is only a single class in it. It seems overkill to have an entire package, which makes it more inconvenient, for a single class.

## How was this patch tested?
Tests were moved.

Author: Reynold Xin <rxin@databricks.com>

Closes #13207 from rxin/SPARK-15424.

## What changes were proposed in this pull request?
Renaming the streaming-kafka artifact to include kafka version, in anticipation of needing a different artifact for later kafka versions

## How was this patch tested?
Unit tests

Author: cody koeninger <cody@koeninger.org>

Closes #12946 from koeninger/SPARK-15085.

## What changes were proposed in this pull request?

This PR creates a compatibility module in sql (called `hive-1-x-compatibility`), which will host HiveContext in Spark 2.0 (moving HiveContext to here will be done separately). This module is not included in assembly because only users who still want to access HiveContext need it.

## How was this patch tested?
I manually tested `sbt/sbt -Phive package` and `mvn -Phive package -DskipTests`.

Author: Yin Huai <yhuai@databricks.com>

Closes #12580 from yhuai/compatibility.

This change modifies the "assembly/" module to just copy needed
dependencies to its build directory, and modifies the packaging
script to pick those up (and remove duplicate jars packages in the
examples module).

I also made some minor adjustments to dependencies to remove some
test jars from the final packaging, and remove jars that conflict with each
other when packaged separately (e.g. servlet api).

Also note that this change restores guava in applications' classpaths, even
though it's still shaded inside Spark. This is now needed for the Hadoop
libraries that are packaged with Spark, which now are not processed by
the shade plugin.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #11796 from vanzin/SPARK-13579.

## What changes were proposed in this pull request?

This PR moves flume back to Spark as per the discussion in the dev mail-list.

## How was this patch tested?

Existing Jenkins tests.

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #11895 from zsxwing/move-flume-back.

[SPARK-13843][STREAMING] Remove streaming-flume, streaming-mqtt, streaming-zeromq, streaming-akka, streaming-twitter to Spark packages

## What changes were proposed in this pull request?

Currently there are a few sub-projects, each for integrating with different external sources for Streaming.  Now that we have better ability to include external libraries (spark packages) and with Spark 2.0 coming up, we can move the following projects out of Spark to https://github.com/spark-packages

- streaming-flume
- streaming-akka
- streaming-mqtt
- streaming-zeromq
- streaming-twitter

They are just some ancillary packages and considering the overhead of maintenance, running tests and PR failures, it's better to maintain them out of Spark. In addition, these projects can have their different release cycles and we can release them faster.

I have already copied these projects to https://github.com/spark-packages

## How was this patch tested?

Jenkins tests

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #11672 from zsxwing/remove-external-pkg.

## What changes were proposed in this pull request?

PR #11443 temporarily disabled MiMA check, this PR re-enables it.

One extra change is that `object DataFrame` is also removed. The only purpose of introducing `object DataFrame` was to use it as an internal factory for creating `Dataset[Row]`. By replacing this internal factory with `Dataset.newDataFrame`, both `DataFrame` and `DataFrame$` are entirely removed from the API, so that we can simply put a `MissingClassProblem` filter in `MimaExcludes.scala` for most DataFrame API  changes.

## How was this patch tested?

Tested by MiMA check triggered by Jenkins.

Author: Cheng Lian <lian@databricks.com>

Closes #11656 from liancheng/re-enable-mima.

This patch removes the need to build a full Spark assembly before running the `dev/mima` script.

- I modified the `tools` project to remove a direct dependency on Spark, so `sbt/sbt tools/fullClasspath` will now return the classpath for the `GenerateMIMAIgnore` class itself plus its own dependencies.
   - This required me to delete two classes full of dead code that we don't use anymore
- `GenerateMIMAIgnore` now uses [ClassUtil](http://software.clapper.org/classutil/) to find all of the Spark classes rather than our homemade JAR traversal code. The problem in our own code was that it didn't handle folders of classes properly, which is necessary in order to generate excludes with an assembly-free Spark build.
- `./dev/mima` no longer runs through `spark-class`, eliminating the need to reason about classpath ordering between `SPARK_CLASSPATH` and the assembly.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #11178 from JoshRosen/remove-assembly-in-run-tests.

## What changes were proposed in this pull request?

This PR unifies DataFrame and Dataset by migrating existing DataFrame operations to Dataset and make `DataFrame` a type alias of `Dataset[Row]`.

Most Scala code changes are source compatible, but Java API is broken as Java knows nothing about Scala type alias (mostly replacing `DataFrame` with `Dataset<Row>`).

There are several noticeable API changes related to those returning arrays:

1.  `collect`/`take`

    -   Old APIs in class `DataFrame`:

        ```scala
        def collect(): Array[Row]
        def take(n: Int): Array[Row]
        ```

    -   New APIs in class `Dataset[T]`:

        ```scala
        def collect(): Array[T]
        def take(n: Int): Array[T]

        def collectRows(): Array[Row]
        def takeRows(n: Int): Array[Row]
        ```

    Two specialized methods `collectRows` and `takeRows` are added because Java doesn't support returning generic arrays. Thus, for example, `DataFrame.collect(): Array[T]` actually returns `Object` instead of `Array<T>` from Java side.

    Normally, Java users may fall back to `collectAsList` and `takeAsList`.  The two new specialized versions are added to avoid performance regression in ML related code (but maybe I'm wrong and they are not necessary here).

1.  `randomSplit`

    -   Old APIs in class `DataFrame`:

        ```scala
        def randomSplit(weights: Array[Double], seed: Long): Array[DataFrame]
        def randomSplit(weights: Array[Double]): Array[DataFrame]
        ```

    -   New APIs in class `Dataset[T]`:

        ```scala
        def randomSplit(weights: Array[Double], seed: Long): Array[Dataset[T]]
        def randomSplit(weights: Array[Double]): Array[Dataset[T]]
        ```

    Similar problem as above, but hasn't been addressed for Java API yet.  We can probably add `randomSplitAsList` to fix this one.

1.  `groupBy`

    Some original `DataFrame.groupBy` methods have conflicting signature with original `Dataset.groupBy` methods.  To distinguish these two, typed `Dataset.groupBy` methods are renamed to `groupByKey`.

Other noticeable changes:

1.  Dataset always do eager analysis now

    We used to support disabling DataFrame eager analysis to help reporting partially analyzed malformed logical plan on analysis failure.  However, Dataset encoders requires eager analysi during Dataset construction.  To preserve the error reporting feature, `AnalysisException` now takes an extra `Option[LogicalPlan]` argument to hold the partially analyzed plan, so that we can check the plan tree when reporting test failures.  This plan is passed by `QueryExecution.assertAnalyzed`.

## How was this patch tested?

Existing tests do the work.

## TODO

- [ ] Fix all tests
- [ ] Re-enable MiMA check
- [ ] Update ScalaDoc (`since`, `group`, and example code)

Author: Cheng Lian <lian@databricks.com>
Author: Yin Huai <yhuai@databricks.com>
Author: Wenchen Fan <wenchen@databricks.com>
Author: Cheng Lian <liancheng@users.noreply.github.com>

Closes #11443 from liancheng/ds-to-df.

## What changes were proposed in this pull request?

This PR fixes typos in comments and testcase name of code.

## How was this patch tested?

manual.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11481 from dongjoon-hyun/minor_fix_typos_in_code.

## What changes were proposed in this pull request?

The PR fixes typos in an error message in dev/run-tests.py.

Author: Wojciech Jurczyk <wojciech.jurczyk@codilime.com>

Closes #11467 from wjur/wjur/typos_run_tests.

There's a minor bug in how we handle the `root` module in the `modules_to_test()` function in `dev/run-tests.py`: since `root` now depends on `build` (since every test needs to run on any build test), we now need to check for the presence of root in `modules_to_test` instead of `changed_modules`.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10933 from JoshRosen/build-module-fix.

This patch improves our `dev/run-tests` script to test modules in a topologically-sorted order based on modules' dependencies.  This will help to ensure that bugs in upstream projects are not misattributed to downstream projects because those projects' tests were the first ones to exhibit the failure

Topological sorting is also useful for shortening the feedback loop when testing pull requests: if I make a change in SQL then the SQL tests should run before MLlib, not after.

In addition, this patch also updates our test module definitions to split `sql` into `catalyst`, `sql`, and `hive` in order to allow more tests to be skipped when changing only `hive/` files.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10885 from JoshRosen/SPARK-8725.

This reverts commit 591c88c9. `lint-java` doesn't work on a machine with a clean Maven cache.

This patch adds a Hadoop 2.7 build profile in order to let us automate tests against that version.

/cc rxin srowen

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10775 from JoshRosen/add-hadoop-2.7-profile.

It was previously turned off because there was a problem with a pull request. We should turn it on now.

Author: Reynold Xin <rxin@databricks.com>

Closes #10763 from rxin/SPARK-12829.

[SPARK-12821][BUILD] Style checker should run when some configuration files for style are modified but any source files are not.

When running the `run-tests` script, style checkers run only when any source files are modified but they should run when configuration files related to style are modified.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #10754 from sarutak/SPARK-12821.

rxin davies shivaram
Took save mode from my PR #10480, and move everything to writer methods. This is related to PR #10559

- [x] it seems jsonRDD() is broken, need to investigate - this is not a public API though; will look into some more tonight. (fixed)

Author: felixcheung <felixcheung_m@hotmail.com>

Closes #10584 from felixcheung/rremovedeprecated.

Author: Reynold Xin <rxin@databricks.com>

Closes #10559 from rxin/remove-deprecated-sql.

[SPARK-10359][PROJECT-INFRA] Use more random number in dev/test-dependencies.sh; fix version switching

This patch aims to fix another potential source of flakiness in the `dev/test-dependencies.sh` script.

pwendell's original patch and my version used `$(date +%s | tail -c6)` to generate a suffix to use when installing temporary Spark versions into the local Maven cache, but this value only changes once per second and thus is highly collision-prone when concurrent builds launch on AMPLab Jenkins. In order to reduce the potential for conflicts, this patch updates the script to call Python's random number generator instead.

I also fixed a bug in how we captured the original project version; the bug was causing the exit handler code to fail.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10558 from JoshRosen/build-dep-tests-round-3.

There are a couple of places in the `dev/run-tests-*.py` scripts which deal with Hadoop profiles, but the set of profiles that they handle does not include all Hadoop profiles defined in our POM. Similarly, the `hadoop-2.2` and `hadoop-2.6` profiles were missing from `dev/deps`.

This patch updates these scripts to include all four Hadoop profiles defined in our POM.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10565 from JoshRosen/add-missing-hadoop-profiles-in-test-scripts.

This patch adds a new build check which enumerates Spark's resolved runtime classpath and saves it to a file, then diffs against that file to detect whether pull requests have introduced dependency changes. The aim of this check is to make it simpler to reason about whether pull request which modify the build have introduced new dependencies or changed transitive dependencies in a way that affects the final classpath.

This supplants the checks added in SPARK-4123 / #5093, which are currently disabled due to bugs.

This patch is based on pwendell's work in #8531.

Closes #8531.

Author: Josh Rosen <joshrosen@databricks.com>
Author: Patrick Wendell <patrick@databricks.com>

Closes #10461 from JoshRosen/SPARK-10359.

fix an exception with IBM JDK by removing update field from a JavaVersion tuple. This is because IBM JDK does not have information on update '_xx'

Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>

Closes #10463 from kiszk/SPARK-12502.

i.e. Hadoop 1 and Hadoop 2.0

Author: Reynold Xin <rxin@databricks.com>

Closes #10404 from rxin/SPARK-11807.

This replaces https://github.com/apache/spark/pull/9696

Invoke Checkstyle and print any errors to the console, failing the step.
Use Google's style rules modified according to
https://cwiki.apache.org/confluence/display/SPARK/Spark+Code+Style+Guide
Some important checks are disabled (see TODOs in `checkstyle.xml`) due to
multiple violations being present in the codebase.

Suggest fixing those TODOs in a separate PR(s).

More on Checkstyle can be found on the [official website](http://checkstyle.sourceforge.net/).

Sample output (from [build 46345](https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/46345/consoleFull)) (duplicated because I run the build twice with different profiles):

> Checkstyle checks failed at following occurrences:
[ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/UnsafeRowParquetRecordReader.java:[217,7] (coding) MissingSwitchDefault: switch without "default" clause.
> [ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/SpecificParquetRecordReaderBase.java:[198,10] (modifier) ModifierOrder: 'protected' modifier out of order with the JLS suggestions.
> [ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/UnsafeRowParquetRecordReader.java:[217,7] (coding) MissingSwitchDefault: switch without "default" clause.
> [ERROR] src/main/java/org/apache/spark/sql/execution/datasources/parquet/SpecificParquetRecordReaderBase.java:[198,10] (modifier) ModifierOrder: 'protected' modifier out of order with the JLS suggestions.
> [error] running /home/jenkins/workspace/SparkPullRequestBuilder2/dev/lint-java ; received return code 1

Also fix some of the minor violations that didn't require sweeping changes.

Apologies for the previous botched PRs - I finally figured out the issue.

cr: JoshRosen, pwendell

> I state that the contribution is my original work, and I license the work to the project under the project's open source license.

Author: Dmitry Erastov <derastov@gmail.com>

Closes #9867 from dskrvk/master.

…n_tests

Author: Jeff Zhang <zjffdu@apache.org>

Closes #9295 from zjffdu/SPARK-11342.