Switch to Java 8

[doanduyhai]

What is this PR for?

Java 7 is now officially no longer supported by Oracle and Java 8 has been released quite a while. We should take the opportunity to switch to Java 8.

What type of PR is it?

[Improvement]

Todos

• - Task

Is there a relevant Jira issue?

ZEPPELIN-621

How should this be tested?

• Hava Java 8 installed locally
• Build Zeppelin with mvn clean -Pxxxx -DskipTests
• Create some notes with spark/angular/shell interpreter and test some basic use-case

This PR is low risk because Java 8 is backward-compatible with Java 7 source code.

Screenshots (if appropriate)

N/A

Questions:

• Does the licenses files need update? --> No
• Is there breaking changes for older versions? --> No
• Does this needs documentation? --> No

[felixcheung]

I think we might need this under a profile switch - there are still a lot of companies running JDK 7 - you can see the discussion similarly with Spark here: http://apache-spark-user-list.1001560.n3.nabble.com/Spark-and-Java-8-tt5443.html

What do you think?

[doanduyhai]

@felixcheung I create this PR because Cassandra server version 3.0 is using Java 8. Right now, some of the features of the Cassandra interpreter cannot be tested because it requires pulling the server and so requires using Java 8 for the integration test.

In general, all the drivers that work at client side are still staying under Java 7 or even Java 6. But on the server side, it's not a problem to ask for Java 8 (because officially Java 7 is no longer supported). Since Zeppelin is a server technology, it's not that a big deal.

However it's not an urgent matter, so I'm fine if we do not switch to Java 8 right now.

Maybe we need some feedback from the community

[doanduyhai]

Closing since it's not urgent matter

[felixcheung]

right - feedback would be good. I think it's a great idea but I can't move to JDK 8 yet ;)
thanks for taking the lead on this though.

[anthonycorbacho]

For me massive +1, this will allow us to update some ancient library.

[bzz]

Geode interpreter also depends on 1.8 https://issues.apache.org/jira/browse/ZEPPELIN-375

Would be nice to switch eventually too (i.e through profile at first)

[pranasblk]

+1

[thepolina]

Any news regarding upgrade to java 8?

[pmleveque]

Spark 2.2 requires Java 1.8

[felixcheung]

yes it does. Zeppelin supports older versions of spark though (and other frameworks)

[mf69]

News flash...Java 7 was EOL over 2 years ago.
https://www.java.com/en/download/faq/java_7.xml

What more does it take to get Zeppelin working with Java 8?

[1ambda]

and we have java 9 and Hadoop 3 increased the minimum java version from 7 to 8. Should we start to discuss using JDK 8 by default?

[felixcheung]

I think it's a great idea to move to 8 We need to see what's not supported and so on, and figure out the way to do it.

[mf69]

@doanduyhai since it's fairly urgent now so please consider re-opening the pull request?

[doanduyhai]

@mf69 done, PR re-opened

[alexott]

Why it still not implemented? Spark starting with 2.2.0 works only with Java 8...