Out of memory when saving large mapping object

[MaximMoinat]

And som other warnings about illegal operations:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.cedarsoftware.util.io.MetaUtils (file:/Users/maxim/Develop/OHDSI/WhiteRabbit/release_zips/WhiteRabbit_v0.10.3/repo/com/cedarsoftware/json-io/3.0.1/json-io-3.0.1.jar) to field java.lang.Boolean.value
WARNING: Please consider reporting this to the maintainers of com.cedarsoftware.util.io.MetaUtils
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space

[MaximMoinat]

A quick solution is to increase the amount of memory assigned when running the jar:
In a text editor, open rabbitInAHat.sh (Mac) or rabbitInAHat.bat (Windows) and change the -Xmx option to a larger value. By default this is 1200m, and for me the issue was fixed when increasing this to -Xmx2400m.

exec "$JAVACMD" $JAVA_OPTS -Xmx2400m \
  -classpath "$CLASSPATH" \
  -Dapp.name="rabbitInAHat" \
  -Dapp.pid="$$" \
  -Dapp.repo="$REPO" \
  -Dapp.home="$BASEDIR" \
  -Dbasedir="$BASEDIR" \
  org.ohdsi.rabbitInAHat.RabbitInAHatMain \
  "$@"

[blootsvoets]

The warning is unrelated. Java 11 only warns on certain reflective operations (e.g., changing a private method to public at runtime). In a future Java version, it might prohibit those operations. Sometimes a later version of the library (in this case, json-io) will have fixed the access.

[blootsvoets]

Can you pinpoint in code where the large object is written? It may help to write the object in streaming style rather than collecting the whole dataset in a single object and then write it to disk.

[MaximMoinat]

@blootsvoets The out of memory error is thrown upon creating a string object (json representation of the model).

WhiteRabbit/rabbitinahat/src/main/java/org/ohdsi/rabbitInAHat/dataModel/ETL.java

Lines 137 to 139 in 172f8c3

	public String toJson() {
	return JsonWriter.formatJson(JsonWriter.objectToJson(this));
	}