问题
Windows 8. Everything in the settings is set to UTF-8. Intellij IDEA displays Chinese characters, for example, which means it's really set to Unicode character set, but it displays a box instead of 𝔊 (MATHEMATICAL_FRAKTUR_CAPITAL_G) symbol.
Debugger window:
回答1:
It's likely that the particular font you're using doesn't contain a glyph for that character. Try switching to another font.
来源：https://stackoverflow.com/questions/39289564/why-intellij-idea-doesnt-display-symbol