Fix issues (critical/major) found by Olingo Code Analyse

["Bolz, Michael" <mi...@sap.com>]

Hi All,

since a few days we have a running SonarQube Analyse Job at Apache:
analysis.apache.org/dashboard/index?id=org.apache.olingo%3Aodata-parent <http://analysis.apache.org/dashboard/index?id=org.apache.olingo%3Aodata-parent>

For the upcoming “4.0.0” release of Olingo I suggest that at least the there listed “critical issues” [1] should be removed.
In the best case the “major issues” [2] should be also removed (or at least checked).

It would be very helpful if every developer / committer check if there is a issue listed on the code he has committed (or is familiar with) 
and check / fix the issue.

Please use “OLINGO-750” [3] for commits related to this clean up task.

Kind Regards,
Michael


[1]: https://analysis.apache.org/component_issues?id=org.apache.olingo%3Aodata-parent#resolved=false|severities=CRITICAL <https://analysis.apache.org/component_issues?id=org.apache.olingo:odata-parent#resolved=false%7Cseverities=CRITICAL>
[2]: https://analysis.apache.org/component_issues?id=org.apache.olingo%3Aodata-parent#resolved=false|severities=MAJOR <https://analysis.apache.org/component_issues?id=org.apache.olingo:odata-parent#resolved=false%7Cseverities=MAJOR>
[3]: https://issues.apache.org/jira/browse/OLINGO-750 <https://issues.apache.org/jira/browse/OLINGO-750>