[Bug]: Simple Evaluation: string comparison with null always return success

[fila73]

Apache Hop version?

2.14; 2.16

Java version?

openjdk-jre-17

Operating system

Windows

What happened?

1. multiway merge join (outer join) in pipeline generates null/empty field
2. store field value into variable
3. compare setted variable with empty one using simple evaluation
4. comparison returns true

bug_reproduction.zip

Issue Priority

Priority: 2

Issue Component

Component: Workflows

Edit: it's not pipeline related, so I change component list. to reproduce bug, just use parameters and steps 3 and 4 (hansva's workflow)