We got the following error, one time, from our nightly test run:

test.javafx.scene.Snapshot2Test > testSnapshot2x2TilesSameHeightDefer[2] STANDARD_ERROR
    java.lang.OutOfMemoryError: Java heap space
     at javafx.graphics/com.sun.prism.sw.SWArgbPreTexture.allocateBuffer(SWArgbPreTexture.java:182)
     at javafx.graphics/com.sun.prism.sw.SWTexture.allocate(SWTexture.java:272)
     at javafx.graphics/com.sun.prism.sw.SWRTTexture.<init>(SWRTTexture.java:50)
     at javafx.graphics/com.sun.prism.sw.SWResourceFactory.createRTTexture(SWResourceFactory.java:135)
     at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit$QuantumImage.getRT(QuantumToolkit.java:1363)
     at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit$5.renderWholeImage(QuantumToolkit.java:1502)
     at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit$5.run(QuantumToolkit.java:1627)
     at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
     at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305)
     at javafx.graphics/com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
     at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
     at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
     at javafx.graphics/com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:125)
     at java.base/java.lang.Thread.run(Thread.java:832)
    Exception in snapshot runnable
    ...
test.javafx.scene.Snapshot2Test > testSnapshot2x2TilesSameHeightDefer[2] FAILED


If it persists may need to increase the default heap size.