GUI: How can I find out if certain Unicode characters are supported?

I noticed that Metal L&F doesn't support certain a开发者_如何学Pythonrrow characters from Unicode, while Nimbus and GTK L&Fs do support them.

Unsupported characters are just displayed as: ...

Can I

1. either look up (manually), which L&F supports which Unicode chars,
2. or find it out at runtime?

EDIT: Or, should it only depend on the L&F's default font, my question perhaps should be:

"how do I find out, which Java font supports which Unicode characters?"

You can use the canDisplay method to test if a java.awt.Font object can display a given character. You can typically get the font from GUI components using the getFont() method.

If you know which unicode block contains the arrows you need, you can look it up here. Unfortunately there doesn't seem to be a page for newer JDK's.

Using this piece of code you use almost every Unicode ta.setFont(new java.awt.Font("Segoe UI Emoji", 1, 20));