You clearly don't know how Swing or Eclipse SWT works under the hood.
Java's big strength is that it's a memory safe, compiled, and sandboxed low level platform with over a quarter century of development behind it. But it historically hasn't handled computer graphics well and can feel very slow and bloated when something needs that - like a GUI. That weakness is probably a big reason why Microsoft rewrote Minecraft after they bought it.
- This isn't a scientific approach.