[ZEPPELIN-1695] Enforce pom.xml style while removing useless, unapplied conf
### What is this PR for? **First of all, this PR doesn't affect on runtime application behaivor and existing build processes. Just adding validation and styling** The main goal of this PR is to keep consistency among multiple pom.xml files - added xml-maven-plugin to enforce valid maven conf and xml code style (included in maven verify phase) - while removing 2 invalid `combine.children` conf (they are invalid, useless. see commit messages) - apply 2 space indent according to [maven style guide](https://maven.apache.org/developers/conventions/code.html) For reviewers, most code modification is due to 4064057 (re-indent commit), **so skipping the commit will be helpful to review this**. ### What type of PR is it? [Improvement] ### Todos * [x] - Add maven xml plugin * [x] - Reindent according to maven style guide ### What is the Jira issue? [ZEPPELIN-1695](https://issues.apache.org/jira/browse/ZEPPELIN-1695) ### How should this be tested? CI will do that. Also you can type `mvn xml:validate` usually it takes 10+- seconds. ``` [INFO] Reactor Summary: [INFO] [INFO] Zeppelin ........................................... SUCCESS [ 2.444 s] [INFO] Zeppelin: Interpreter .............................. SUCCESS [ 0.048 s] [INFO] Zeppelin: Zengine .................................. SUCCESS [ 0.029 s] [INFO] Zeppelin: Display system apis ...................... SUCCESS [ 0.025 s] [INFO] Zeppelin: Spark dependencies ....................... SUCCESS [ 0.038 s] [INFO] Zeppelin: Spark .................................... SUCCESS [ 0.040 s] [INFO] Zeppelin: Markdown interpreter ..................... SUCCESS [ 0.022 s] [INFO] Zeppelin: Angular interpreter ...................... SUCCESS [ 0.013 s] [INFO] Zeppelin: Shell interpreter ........................ SUCCESS [ 0.019 s] [INFO] Zeppelin: Livy interpreter ......................... SUCCESS [ 0.018 s] [INFO] Zeppelin: HBase interpreter ........................ SUCCESS [ 0.014 s] [INFO] Zeppelin: Apache Pig Interpreter ................... SUCCESS [ 0.016 s] [INFO] Zeppelin: PostgreSQL interpreter ................... SUCCESS [ 0.012 s] [INFO] Zeppelin: JDBC interpreter ......................... SUCCESS [ 0.012 s] [INFO] Zeppelin: File System Interpreters ................. SUCCESS [ 0.025 s] [INFO] Zeppelin: Flink .................................... SUCCESS [ 0.048 s] [INFO] Zeppelin: Apache Ignite interpreter ................ SUCCESS [ 0.013 s] [INFO] Zeppelin: Kylin interpreter ........................ SUCCESS [ 0.010 s] [INFO] Zeppelin: Python interpreter ....................... SUCCESS [ 0.011 s] [INFO] Zeppelin: Lens interpreter ......................... SUCCESS [ 0.015 s] [INFO] Zeppelin: Apache Cassandra interpreter ............. SUCCESS [ 0.036 s] [INFO] Zeppelin: Elasticsearch interpreter ................ SUCCESS [ 0.014 s] [INFO] Zeppelin: BigQuery interpreter ..................... SUCCESS [ 0.012 s] [INFO] Zeppelin: Alluxio interpreter ...................... SUCCESS [ 0.011 s] [INFO] Zeppelin: Scio ..................................... SUCCESS [ 0.026 s] [INFO] Zeppelin: web Application .......................... SUCCESS [ 1.193 s] [INFO] Zeppelin: Server ................................... SUCCESS [ 0.015 s] [INFO] Zeppelin: Packaging distribution ................... SUCCESS [ 0.022 s] [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 4.678 s [INFO] Finished at: 2016-11-22T00:24:32+09:00 [INFO] Final Memory: 27M/703M [INFO] ------------------------------------------------------------------------ ``` ### Questions: * Does the licenses files need update? NO * Is there breaking changes for older versions? NO * Does this needs documentation? NO Author: 1ambda <1am...@gmail.com> Closes #1662 from 1ambda/feat/check-pom-file-is-well-formed and squashes the following commits: 2d8d7d2 [1ambda] fix: Remove useless combine.children=append f858a16 [1ambda] fix: Use _tools/maven-4.0.0.xsd 1142b46 [1ambda] fix: Remove useless encoding options 03579e7 [1ambda] fix: Remove useless combine.chdilren 4418cad [1ambda] feat: Add xml-maven-plugin to validate pom.xml Project: http://git-wip-us.apache.org/repos/asf/zeppelin/repo Commit: http://git-wip-us.apache.org/repos/asf/zeppelin/commit/5595bfb9 Tree: http://git-wip-us.apache.org/repos/asf/zeppelin/tree/5595bfb9 Diff: http://git-wip-us.apache.org/repos/asf/zeppelin/diff/5595bfb9 Branch: refs/heads/master Commit: 5595bfb9d06267712505dd9d3f4479d16a54aef8 Parents: 3be4b82 Author: 1ambda <1am...@gmail.com> Authored: Tue Nov 22 00:17:03 2016 +0900 Committer: Alexander Bezzubov <b...@apache.org> Committed: Thu Nov 24 18:31:41 2016 +0900 ---------------------------------------------------------------------- _tools/maven-4.0.0.xsd | 2484 +++++++++++++++++++++++++++++++++++++++++ pom.xml | 38 +- zeppelin-zengine/pom.xml | 2 +- 3 files changed, 2519 insertions(+), 5 deletions(-) ----------------------------------------------------------------------
