[Bug]: NullPointerException when Enhanced JSON Output receives an empty stream

[bamaer]

Apache Hop version?

SNAPSHOT-20230513

Java version?

openjdk version "11.0.18" 2023-01-17

Operating system

Linux

What happened?

NPE when Enhanced JSON Output is configured to write to a file and receives an empty stream.
This issue does not occur when only "Output value" is selected.

org.apache.hop.core.exception.HopTransformException: 
Error writing to file!
 at java.lang.Thread.run (Thread.java:829)
 at org.apache.hop.pipeline.transform.RunThread.run (RunThread.java:55)
 at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.processRow (JsonOutput.java:111)
 at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.writeJsonFile (JsonOutput.java:331)
 at java.io.Writer.write (Writer.java:249)

        at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.writeJsonFile(JsonOutput.java:333)
        at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.processRow(JsonOutput.java:111)
        at org.apache.hop.pipeline.transform.RunThread.run(RunThread.java:55)
        at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.lang.NullPointerException
        at java.base/java.io.Writer.write(Writer.java:249)
        at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.writeJsonFile(JsonOutput.java:331)
        ... 3 more
2023/05/13 09:05:39 - Enhanced JSON Output.0 - ERROR: Unexpected error
2023/05/13 09:05:39 - Enhanced JSON Output.0 - ERROR: org.apache.hop.core.exception.HopTransformException: 
2023/05/13 09:05:39 - Enhanced JSON Output.0 - Error writing to file!
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at java.lang.Thread.run (Thread.java:829)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transform.RunThread.run (RunThread.java:55)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.processRow (JsonOutput.java:111)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.writeJsonFile (JsonOutput.java:331)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at java.io.Writer.write (Writer.java:249)
2023/05/13 09:05:39 - Enhanced JSON Output.0 - 
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.writeJsonFile(JsonOutput.java:333)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.processRow(JsonOutput.java:111)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transform.RunThread.run(RunThread.java:55)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at java.base/java.lang.Thread.run(Thread.java:829)
2023/05/13 09:05:39 - Enhanced JSON Output.0 - Caused by: java.lang.NullPointerException
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at java.base/java.io.Writer.write(Writer.java:249)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  at org.apache.hop.pipeline.transforms.jsonoutputenhanced.JsonOutput.writeJsonFile(JsonOutput.java:331)
2023/05/13 09:05:39 - Enhanced JSON Output.0 -  ... 3 more
2023/05/13 09:05:39 - Enhanced JSON Output.0 - Finished processing (I=0, O=0, R=0, W=0, U=0, E=1)

Issue Priority

Priority: 2

Issue Component

Component: Transforms