Java font partially unreadable

after starting “tvbrowser_4.2.2_bin_transportable” some fonts in other java-applications are partially unreadable (can I add a screenshot?); I added this line in ~/bashrc:
export _JAVA_OPTIONS=’-Dawt.useSystemAAFontSettings=lcd’
didn´t have any effect, tried this one:
export _JAVA_OPTIONS=’-Dawt.useSystemAAFontSettings=lcd -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel’
it was just the same; is there any idea how to change the font in java?
java --version
openjdk 15.0.2 2021-01-19
OpenJDK Runtime Environment (build 15.0.2+7)
OpenJDK 64-Bit Server VM (build 15.0.2+7, mixed mode)

ok, thanx, “again what learned” as we say in germany … ;-))