For which surprises do I have to prepare myself if

Question

If I'd switch from Sun JDK to OpenJDK which surprises do I have to prepare myself for?

What does frequently go wrong and how difficult can this be?

Of course, each and every application can have its individual problems, but I'm looking for classes of problems, something many people already have struggled with when switching JDKs.

Answer 1

Use an OpenJDK build known to pass the TCK to minimize the surprises.

Answer 2

As I know fonts will look garbled, Sun had to remove original ones from OpenJDK since they are not 'open source' and JVM will use some default which are not so nice...

Answer 3

OpenJDK is more secure than the Oracle binaries because of IcedTea.

Answer 4

Some of the swing UI's did not match up entirely (metal had paddings that were off just aenough to notice). Note that this was 8 months ago.

Answer 5

OpenJDK (IcedTea) applets under linux are a MAJOR PAIN. I'm struggling with remote debugging a piece of rather rusty code for couple of hours already. Official documentation on how to attach to an applet in a browser simply does not work for me. There's no java console by default, BTW. I'm seriously considering replicating the applet config and using JDK built-in applet viewer instead of trying to debug the browser-hosted JVM.

UPD: I am not quite sure that OpenJDK does not have a browser plugin itself. Maybe this changed recently.

Answer 6

Since OpenJDK is a Sun project, based on the original Java source, I wouldn't expect many problems. The only area where things can break is the code which had to be replaced (because it couldn't be released under the GPL) or changes because of new features (but those should be pretty much the same as in the official JDK).