The language is an enormous success. But in one key area it did not succeed in popularity: in building cross-platform desktop GUI apps.
Many businesses did use it for building internal GUI desktop apps. However, Java did not find much success in consumer-facing desktop apps - despite the considerable effort made to encourage developers use Java for this purpose. For example, in the late 1990s Java had it's own GUI look-and-feel called 'Flush 3D'. It was designed to be consistent across operating systems.[1]
But Java desktop apps earned the reputation as being slow and unresponsive, not fast and nimble. The Java applets that ran in the browser were no better. Today, perhaps Java will find success creating consumer-facing, high-performance applications on web pages using WebAssembly?