In JCP in sv, \u00C5 is used as mnemonic.
Deployment_sv.java:
{ "cert.restore_dialog.btn_restore.text", "&\u00C5terst\u00E4ll alla"},
{ "security.certificates.restore_button.text", "&\u00C5terst\u00E4ll s\u00E4kerhetsmeddelanden"},
{ "cache.settings.dialog.restore_btn", "&\u00C5terst\u00E4ll standardv\u00E4rden" },

Some others:
 { "deploy.jre.find.button", "S&\u00F6k" },
 { "cache.settings.dialog.change_btn", "&\u00C4ndra..." },

According to the Java API:
A mnemonic must correspond to a single key on the keyboard and should be specified using one of the VK_XXX keycodes defined in java.awt.event.KeyEvent.

Those mnemonic keys are not in the keycodes in java.awt.event.KeyEvent and can not be displayed in JCP. English characters in the text should be used as mnemonic keys.