https://www.gitmemory.com/issue/karakun/OpenWebStart/384/769858773
Meanwhile I followed another hint and tried adding the add-exports/add-opens to the main jar MANIFEST.MF - this does not work either.
Add-Opens: java.desktop/javax.swing.plaf.synth java.desktop/javax.swin
g.plaf.basic java.desktop/javax.swing java.desktop/javax.swing.tree j
ava.desktop/java.awt.event java.base/java.lang java.base/sun.security
.action java.base/java.security java.base/java.util.concurrent java.d
esktop/java.beans
Add-Exports: java.desktop/sun.swing java.desktop/sun.swing.table java.
desktop/sun.swing.plaf.synth java.desktop/com.sun.java.swing.plaf.win
dows java.desktop/sun.awt.shell java.desktop/com.sun.awt java.base/su
n.security.action java.base/java.lang
ps:
反编译jar包后不要忘记修改自己的MANIFEST.MF文件
java.lang.NoClassDefFoundError: sun/swing/plaf/synth/SynthIcon
原文：https://www.cnblogs.com/DirWang/p/14982133.html