(Updated version of [PR-9457](https://github.com/apache/spark/pull/9457), rebased on latest Spark master, and using mllib-local).

This implements a parallel version of personalized pagerank, which runs all propagations for a list of source vertices in parallel.

I ran a few benchmarks on the full [DBpedia](http://dbpedia.org/) graph. When running personalized pagerank for only one source node, the existing implementation is twice as fast as the parallel one (because of the SparseVector overhead). However for 10 source nodes, the parallel implementation is four times as fast. When increasing the number of source nodes, this difference becomes even greater.

![image](https://cloud.githubusercontent.com/assets/2491/10927702/dd82e4fa-8256-11e5-89a8-4799b407f502.png)

Author: Yves Raimond <yraimond@netflix.com>

Closes #14998 from moustaki/parallel-ppr.

[SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting

## What changes were proposed in this pull request?

Avoid using postfix operation for command execution in SQLQuerySuite where it wasn't whitelisted and audit existing whitelistings removing postfix operators from most places. Some notable places where postfix operation remains is in the XML parsing & time units (seconds, millis, etc.) where it arguably can improve readability.

## How was this patch tested?

Existing tests.

Author: Holden Karau <holden@us.ibm.com>

Closes #14407 from holdenk/SPARK-16779.

[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.

## What changes were proposed in this pull request?

I added caching in every iteration for sccGraph that is returned in strongly connected components. Without this cache strongly connected components returned graph that needed to be computed from scratch when some intermediary caches didn't existed anymore.

## How was this patch tested?
I tested it by running code similar to the one  [on databrics](https://databricks-prod-cloudfront.cloud.databricks.com/public/4027ec902e239c93eaaa8714f173bcfc/4889410027417133/3634650767364730/3117184429335832/latest.html). Basically I generated large graph  and computed strongly connected components with changed code, than simply run count on vertices and edges. Count after this update takes few seconds instead 20 minutes.

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

Author: Michał Wesołowski <michal.wesolowski@bzwbk.pl>

Closes #14137 from wesolowskim/SPARK-16478.

[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.

[SPARK-3359][DOCS] More changes to resolve javadoc 8 errors that will help unidoc/genjavadoc compatibility

## What changes were proposed in this pull request?

These are yet more changes that resolve problems with unidoc/genjavadoc and Java 8. It does not fully resolve the problem, but gets rid of as many errors as we can from this end.

## How was this patch tested?

Jenkins build of docs

Author: Sean Owen <sowen@cloudera.com>

Closes #14221 from srowen/SPARK-3359.3.

## What changes were proposed in this pull request?
After SPARK-16476 (committed earlier today as #14128), we can finally bump the version number.

## How was this patch tested?
N/A

Author: Reynold Xin <rxin@databricks.com>

Closes #14130 from rxin/SPARK-16477.

## What changes were proposed in this pull request?

There are two test data files used for graphx examples existing in directory "graphx/data"
I move it into "data/" directory because the "graphx" directory is used for code files and other test data files (such as mllib, streaming test data) are all in there.

I also update the graphx document where reference the data files which I move place.

## How was this patch tested?

N/A

Author: WeichenXu <WeichenXu123@outlook.com>

Closes #14010 from WeichenXu123/move_graphx_data_dir.

## What changes were proposed in this pull request?

`an -> a`

Use cmds like `find . -name '*.R' | xargs -i sh -c "grep -in ' an [^aeiou]' {} && echo {}"` to generate candidates, and review them one by one.

## How was this patch tested?
manual tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #13515 from zhengruifeng/an_a.

## What changes were proposed in this pull request?

(See https://github.com/apache/spark/pull/12416 where most of this was already reviewed and committed; this is just the module structure and move part. This change does not move the annotations into test scope, which was the apparently problem last time.)

Rename `spark-test-tags` -> `spark-tags`; move common annotations like `Since` to `spark-tags`

## How was this patch tested?

Jenkins tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #13074 from srowen/SPARK-15290.

## What changes were proposed in this pull request?

This PR removes a stale TODO comment in `GraphGenerators.scala`

## How was this patch tested?

Just comment removed.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #12839 from dongjoon-hyun/SPARK-15057.

This reverts commit dae538a4.

## What changes were proposed in this pull request?

This PR adds `since` tag into the matrix and vector classes in spark-mllib-local.

## How was this patch tested?

Scala-style checks passed.

Author: Pravin Gadakh <prgadakh@in.ibm.com>

Closes #12416 from pravingadakh/SPARK-14613.

## What changes were proposed in this pull request?

Minor typo fixes (too minor to deserve separate a JIRA)

## How was this patch tested?

local build

Author: Jacek Laskowski <jacek@japila.pl>

Closes #12469 from jaceklaskowski/minor-typo-fixes.

## What changes were proposed in this pull request?

Spark uses `NewLineAtEofChecker` rule in Scala by ScalaStyle. And, most Java code also comply with the rule. This PR aims to enforce the same rule `NewlineAtEndOfFile` by CheckStyle explicitly. Also, this fixes lint-java errors since SPARK-14465. The followings are the items.

- Adds a new line at the end of the files (19 files)
- Fixes 25 lint-java errors (12 RedundantModifier, 6 **ArrayTypeStyle**, 2 LineLength, 2 UnusedImports, 2 RegexpSingleline, 1 ModifierOrder)

## How was this patch tested?

After the Jenkins test succeeds, `dev/lint-java` should pass. (Currently, Jenkins dose not run lint-java.)
```bash
$ dev/lint-java
Using `mvn` from path: /usr/local/bin/mvn
Checkstyle checks passed.
```

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #12632 from dongjoon-hyun/SPARK-14868.

The current package name uses a dash, which is a little weird but seemed
to work. That is, until a new test tried to mock a class that references
one of those shaded types, and then things started failing.

Most changes are just noise to fix the logging configs.

For reference, SPARK-8815 also raised this issue, although at the time it
did not cause any issues in Spark, so it was not addressed.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #11941 from vanzin/SPARK-14134.

## What changes were proposed in this pull request?

Added an omitted word in the error message displayed by the Graphx Pregel API when `maxIterations <= 0`

## How was this patch tested?

Manual test

Author: Victor Chima <blazy2k9@gmail.com>

Closes #12205 from blazy2k9/hotfix/pregel-error-message.

## What changes were proposed in this pull request?

This PR aims to fix all Scala-Style multiline comments into Java-Style multiline comments in Scala codes.
(All comment-only changes over 77 files: +786 lines, −747 lines)

## How was this patch tested?

Manual.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #12130 from dongjoon-hyun/use_multiine_javadoc_comments.

[SPARK-14219][GRAPHX] Fix `pickRandomVertex` not to fall into infinite loops for graphs with one vertex

## What changes were proposed in this pull request?

Currently, `GraphOps.pickRandomVertex()` falls into infinite loops for graphs having only one vertex. This PR fixes it by modifying the following termination-checking condition.
```scala
-      if (selectedVertices.count > 1) {
+      if (selectedVertices.count > 0) {
```

## How was this patch tested?

Pass the Jenkins tests (including new test case).

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #12018 from dongjoon-hyun/SPARK-14219.

## What changes were proposed in this pull request?

This PR fixes some newly added java-lint errors(unused-imports, line-lengsth).

## How was this patch tested?

Pass the Jenkins tests.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11968 from dongjoon-hyun/SPARK-14167.

## What changes were proposed in this pull request?

Logging was made private in Spark 2.0. If we move it, then users would be able to create a Logging trait themselves to avoid changing their own code.

## How was this patch tested?

existing tests.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #11764 from cloud-fan/logger.

JIRA: https://issues.apache.org/jira/browse/SPARK-13816

## What changes were proposed in this pull request?

Add parameter checks for algorithms in Graphx: Pregel,LabelPropagation,PageRank,SVDPlusPlus

## How was this patch tested?

manual tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #11655 from zhengruifeng/graphx_param_check.

## What changes were proposed in this pull request?

This PR fixes 135 typos over 107 files:
* 121 typos in comments
* 11 typos in testcase name
* 3 typos in log messages

## How was this patch tested?

Manual.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11689 from dongjoon-hyun/fix_more_typos.

[SPARK-13823][CORE][STREAMING][SQL] Always specify Charset in String <-> byte[] conversions (and remaining Coverity items)

## What changes were proposed in this pull request?

- Fixes calls to `new String(byte[])` or `String.getBytes()` that rely on platform default encoding, to use UTF-8
- Same for `InputStreamReader` and `OutputStreamWriter` constructors
- Standardizes on UTF-8 everywhere
- Standardizes specifying the encoding with `StandardCharsets.UTF-8`, not the Guava constant or "UTF-8" (which means handling `UnuspportedEncodingException`)
- (also addresses the other remaining Coverity scan issues, which are pretty trivial; these are separated into commit https://github.com/srowen/spark/commit/1deecd8d9ca986d8adb1a42d315890ce5349d29c )

## How was this patch tested?

Jenkins tests

Author: Sean Owen <sowen@cloudera.com>

Closes #11657 from srowen/SPARK-13823.

## 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?

After SPARK-6990, `dev/lint-java` keeps Java code healthy and helps PR review by saving much time.
This issue aims remove unused imports from Java/Scala code and add `UnusedImports` checkstyle rule to help developers.

## How was this patch tested?
```
./dev/lint-java
./build/sbt compile
```

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11438 from dongjoon-hyun/SPARK-13583.

## What changes were proposed in this pull request?

Make some cross-cutting code improvements according to static analysis. These are individually up for discussion since they exist in separate commits that can be reverted. The changes are broadly:

- Inner class should be static
- Mismatched hashCode/equals
- Overflow in compareTo
- Unchecked warnings
- Misuse of assert, vs junit.assert
- get(a) + getOrElse(b) -> getOrElse(a,b)
- Array/String .size -> .length (occasionally, -> .isEmpty / .nonEmpty) to avoid implicit conversions
- Dead code
- tailrec
- exists(_ == ) -> contains find + nonEmpty -> exists filter + size -> count
- reduce(_+_) -> sum map + flatten -> map

The most controversial may be .size -> .length simply because of its size. It is intended to avoid implicits that might be expensive in some places.

## How was the this patch tested?

Existing Jenkins unit tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #11292 from srowen/SPARK-13423.

## What changes were proposed in this pull request?

This PR tries to fix all typos in all markdown files under `docs` module,
and fixes similar typos in other comments, too.

## How was the this patch tested?

manual tests.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11300 from dongjoon-hyun/minor_fix_typos.

jegonzal ankurdave please could you review

## What changes were proposed in this pull request?

Reworking of jegonzal PR #2495 to address the issue identified in SPARK-3650. Code amended to use the convertToCanonicalEdges method.

## How was the this patch tested?

Patch was tested using the unit tests created in PR #2495

Author: Robin East <robin.east@xense.co.uk>
Author: Joseph E. Gonzalez <joseph.e.gonzalez@gmail.com>

Closes #11290 from insidedctm/spark-3650.

JIRA: https://issues.apache.org/jira/browse/SPARK-13416

## What changes were proposed in this pull request?

The output of StronglyConnectedComponents with numIter no greater than 1 may make no sense. So I just add require check in it.

## How was the this patch tested?

 unit tests passed

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #11284 from zhengruifeng/scccheck.

JIRA: https://issues.apache.org/jira/browse/SPARK-13386

## What changes were proposed in this pull request?

add maxIteration option for ConnectedComponents algorithm

## How was the this patch tested?

unit tests passed

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #11268 from zhengruifeng/ccwithmax.

Author: Takeshi YAMAMURO <linguin.m.s@gmail.com>

Closes #10918 from maropu/RemoveDeprecateInPregel.

This patch changes Spark's build to make Scala 2.11 the default Scala version. To be clear, this does not mean that Spark will stop supporting Scala 2.10: users will still be able to compile Spark for Scala 2.10 by following the instructions on the "Building Spark" page; however, it does mean that Scala 2.11 will be the default Scala version used by our CI builds (including pull request builds).

The Scala 2.11 compiler is faster than 2.10, so I think we'll be able to look forward to a slight speedup in our CI builds (it looks like it's about 2X faster for the Maven compile-only builds, for instance).

After this patch is merged, I'll update Jenkins to add new compile-only jobs to ensure that Scala 2.10 compilation doesn't break.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10608 from JoshRosen/SPARK-6363.

Some VertexRDD and EdgeRDD are created during the intermediate step of g.connectedComponents() but unnecessarily left cached after the method is done. The fix is to unpersist these RDDs once they are no longer in use.

A test case is added to confirm the fix for the reported bug.

Author: Jason Lee <cjlee@us.ibm.com>

Closes #10713 from jasoncl/SPARK-12655.

Fix the style violation (space before `,` and `:`).
This PR is a followup for #10643.

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

Closes #10683 from sarutak/SPARK-12692-followup-graphx.

[SPARK-12665][CORE][GRAPHX] Remove Vector, VectorSuite and GraphKryoRegistrator which are deprecated and no longer used

Whole code of Vector.scala, VectorSuite.scala and GraphKryoRegistrator.scala  are no longer used so it's time to remove them in Spark 2.0.

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

Closes #10613 from sarutak/SPARK-12665.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #10582 from vanzin/SPARK-3873-tests.

There's one warning left, caused by a bug in the checker.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #10537 from vanzin/SPARK-3873-graphx.

Author: Takeshi YAMAMURO <linguin.m.s@gmail.com>

Closes #4674 from maropu/AddGraphLoaderSuite.

Author: Reynold Xin <rxin@databricks.com>

Closes #10387 from rxin/version-bump.