[SPARK-25984] Remove deprecated .newInstance(), primitive wrapper class constructor calls

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.0.0
• Component/s: Spark Core, SQL, Structured Streaming
• Target Version/s: 3.0.0
• Assignee: Sean R. Owen
• Reporter: Sean R. Owen
• Created: 08/Nov/18 23:13
• Updated: 10/Nov/18 15:52
• Resolved: 10/Nov/18 15:52

Description

While working on JDK 11 support, I noticed a lot of new deprecation warnings. 80% of them seem to be from two easily-fixable sources:

• Class.newInstance() is deprecated
• Almost all constructors from primitive wrapper classes like Integer are deprecated

These are easy to fix because there have long been equivalent, better alternatives:

• Just call .getConstructor().newInstance()
• Replace new Integer with Integer.valueOf, etc

The latter has the advantage, for integral types, of not even allocating a new object for small values.

We should just fix these to clean up the build output.

Issue Links

• links to: [Github] Pull Request #22988 (srowen)