NPE upon captcha generation

Play supports Java 11 since 1.5.3 (https://github.com/playframework/play1/releases/tag/1.5.3) and everything seems to work well.

However, I noticed that, although captchas are correctly generated using

 Images.Captcha captcha = Images.captcha();
 renderBinary(captcha);

logs show a NullPointerException - see stack trace below.

When using Java 8, no NullPointerException is thrown.

Does anyone know about a fix for this?

The following ticket has been created: https://github.com/playframework/play1/issues/1326

Stack trace:

java.lang.NullPointerException
	at jj.play.ns.com.jhlabs.image.TransformFilter.imageComplete(TransformFilter.java)
	at java.desktop/sun.awt.image.OffScreenImageSource.produce(OffScreenImageSource.java:193)
	at java.desktop/sun.awt.image.OffScreenImageSource.addConsumer(OffScreenImageSource.java:66)
	at java.desktop/sun.awt.image.OffScreenImageSource.startProduction(OffScreenImageSource.java:80)
	at java.desktop/java.awt.image.FilteredImageSource.startProduction(FilteredImageSource.java:184)
	at java.desktop/sun.awt.image.ImageRepresentation.startProduction(ImageRepresentation.java:732)
	at java.desktop/sun.awt.image.ToolkitImage.addWatcher(ToolkitImage.java:221)
	at java.desktop/sun.awt.image.ToolkitImage.getWidth(ToolkitImage.java:110)
	at java.desktop/sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:3407)
	at jj.play.ns.nl.captcha.util.ImageUtil.applyFilter(Unknown Source)
	at jj.play.ns.nl.captcha.gimpy.RippleGimpyRenderer.gimp(Unknown Source)
	at play.libs.Images$Captcha.check(Images.java:423)
	at play.libs.Images$Captcha.read(Images.java:406)
	at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:2146)
	at org.apache.commons.io.IOUtils.copy(IOUtils.java:2102)
	at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:2123)
	at play.mvc.results.RenderBinary.copyInputStreamAndClose(RenderBinary.java:207)
	at play.mvc.results.RenderBinary.renderInputStream(RenderBinary.java:197)
	at play.mvc.results.RenderBinary.apply(RenderBinary.java:157)
	at play.mvc.ActionInvoker.invoke(ActionInvoker.java:201)
	at play.server.PlayHandler$NettyInvocation.execute(PlayHandler.java:289)
	at play.Invoker$Invocation$1.apply(Invoker.java:319)
	at play.Invoker$Invocation$1.apply(Invoker.java:315)
	at play.db.jpa.JPA.withTransaction(JPA.java:349)
	at play.db.jpa.JPA.withinFilter(JPA.java:238)
	at play.db.jpa.JPAPlugin$TransactionalFilter.withinFilter(JPAPlugin.java:306)
	at play.Invoker$Invocation.withinFilter(Invoker.java:298)
	at play.Invoker$Invocation.run(Invoker.java:315)
	at play.server.PlayHandler$NettyInvocation.run(PlayHandler.java:266)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)