Due to a bug in my app, the update4j xml generated ended up with a 0b file size instead of correct size(65mo), leading to this exception in the client using that xml:

Part of the XML file:

file uri="http://files.yildiz-games.be/play50hz/player/retro-player.jar" path="${user.dir}/lib/retro-player.jar" size="0" checksum="1"

Exception:

Downloading 0 B 0% [> ] Exception in thread "Progress Printer" java.lang.OutOfMemoryError: Java heap space
at java.base/java.util.Arrays.copyOf(Unknown Source)
at java.base/java.util.StringJoiner.add(Unknown Source)
at java.base/java.lang.String.join(Unknown Source)
at org.update4j.util.StringUtils.repeat(StringUtils.java:123)
at org.update4j.service.DefaultUpdateHandler.renderProgress(DefaultUpdateHandler.java:189)
at org.update4j.service.DefaultUpdateHandler$1.run(DefaultUpdateHandler.java:127)
at java.base/java.util.TimerThread.mainLoop(Unknown Source)
at java.base/java.util.TimerThread.run(Unknown Source)

Same file with expected size(65mo) is handled correctly.