Under Java for macOS there is currently no standard way to change the title bar mode from regular to dark or transparent. Both are modes supported by the underlying Cocoa framework (NSAppearance). This is desirable to make sure that Java applications can look just as good under macOS as native applications. NetBeans and its Darcula LAF will also benefit from this.

Please provide a method to set arbitrary modes, e.g. via client properties, as it is already done in the JetBrains JDK. I.e. like

getRootPane().putClientProperty("jetbrains.awt.windowDarkAppearance", true);

See https://twitter.com/dsfokin/status/869488465804750849 for a link to an implementation (binary).

The attached screenshot shows an application running under the JetBrains JDK.

A back port of the solution to Java 8 would be highly appreciated.