Version 1.53j, ij.io.Opener no longer works on headless

[rudolphi]

Throws

Caused by: java.awt.HeadlessException
	at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:204)
	at java.awt.MenuComponent.<init>(MenuComponent.java:163)
	at java.awt.MenuItem.<init>(MenuItem.java:214)
	at java.awt.MenuItem.<init>(MenuItem.java:198)
	at java.awt.Menu.<init>(Menu.java:157)
	at java.awt.Menu.<init>(Menu.java:137)
	at ij.Menus.getMenu(Menus.java:849)
	at ij.Menus.getMenu(Menus.java:839)
	at ij.Menus.addMenuBar(Menus.java:109)
	at ij.IJ.init(IJ.java:422)
	at ij.Menus.getCommands(Menus.java:1339)
	at ij.io.Opener.<clinit>(Opener.java:47)
	...

[ctrueden]

@rudolphi With which version of the original ImageJ was this working for you? In a BeakerX Groovy notebook, using the following code:

%classpath add mvn net.imagej:ij:1.53d
System.setProperty("java.awt.headless", "true")
blobs = new ij.io.Opener().open("/home/curtis/data/blobs.tif")

I receive:

java.awt.HeadlessException
	at ij.gui.ImageWindow.<init>(ImageWindow.java:70)
	at ij.gui.ImageWindow.<init>(ImageWindow.java:66)
	at ij.ImagePlus.show(ImagePlus.java:486)
	at ij.io.Opener.open(Opener.java:117)

So it doesn't work with 1.53d either. And same error with 1.53a.

Are you using ImageJ2/Fiji, or plain ImageJ?

Assuming ImageJ2/Fiji, I took the liberty of transferring this issue into the imagej-legacy repo. Please note that ImageJ2 adds headless patching on top of the original ImageJ, to enable better headless support, so I took the liberty of moving your issue here to imagej-legacy, which (along with ij1-patcher) is the project responsible for this patching. Be aware that the newest version of ImageJ officially supported by the ImageJ2 patching mechanism is currently 1.53f. I would not recommend updating the ImageJ core beyond that until we get the patching mechanism updated to support ImageJ's latest code changes.

[rudolphi]

I am using groupId=net.imagej, artifactId=ij. The problem is the IJ.init() that has been added to Menus.getCommands() if pluginsTable is null. Menus.getCommands() is called during class initialization.

[ctrueden]

@rudolphi OK, I transferred the issue back to the original ImageJ repository, then.

With which version of ImageJ are you able to use ij.io.Opener headless?

[rudolphi]

It works smoothly with 1.53i

[ctrueden]

@rudolphi Ah I see, I was testing the wrong thing. I was using Opener#open(String), but that tries to show the image. The Opener#openImage(String) method, which returns ImagePlus, does indeed work headless with 1.53i for me:

$ echo 'public class X { public static void main(String[] args) { System.out.println(new ij.io.Opener().openImage(args[0])); } }' > X.java
$ mvn dependency:get -Dartifact=net.imagej:ij:1.53i
$ javac -cp ~/.m2/repository/net/imagej/ij/1.53i/ij-1.53i.jar X.java
$ java -Djava.awt.headless=true -cp ~/.m2/repository/net/imagej/ij/1.53i/ij-1.53i.jar:. X ~/data/blobs.tif
img["blobs.tif" (-2), 8-bit, 256x254x1x1x1]

And with 1.53j:

$ mvn dependency:get -Dartifact=net.imagej:ij:1.53i
$ java -Djava.awt.headless=true -cp ~/.m2/repository/net/imagej/ij/1.53j/ij-1.53j.jar:. X ~/data/blobs.tif
Exception in thread "main" java.lang.ExceptionInInitializerError
	at X.main(X.java:1)
Caused by: java.awt.HeadlessException
	at java.desktop/java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:165)
	at java.desktop/java.awt.MenuComponent.<init>(MenuComponent.java:181)
	at java.desktop/java.awt.MenuItem.<init>(MenuItem.java:224)
	at java.desktop/java.awt.MenuItem.<init>(MenuItem.java:208)
	at java.desktop/java.awt.Menu.<init>(Menu.java:163)
	at java.desktop/java.awt.Menu.<init>(Menu.java:144)
	at ij.Menus.getMenu(Menus.java:849)
	at ij.Menus.getMenu(Menus.java:839)
	at ij.Menus.addMenuBar(Menus.java:109)
	at ij.IJ.init(IJ.java:422)
	at ij.Menus.getCommands(Menus.java:1339)
	at ij.io.Opener.<clinit>(Opener.java:47)
	... 1 more

So @rasband this is an issue introduced in b553ff4, which as @rudolphi points out, adds an IJ.init() call to Menus.getCommands(). Would it make sense to test for headless mode in Menus#getMenu(String, boolean) and return null in that case?

[rasband]

This bug should be fixed in the ImageJ 1.53o20 daily build. The Menus.getCommands() method now has a test for headless mode.

   public static Hashtable getCommands() {
      if (pluginsTable==null && !GraphicsEnvironment.isHeadless())
          IJ.init();
      return pluginsTable;
   }