This was the old GRECLIPSE-1761:

Consider the following Java class:

package m; public class JavaClass<T extends Number> { }

And the following Groovy class:

package m 

class M { 
	JavaClass<Integer> foo = new JavaCl| 
} 

Invoke code assist at "|" and choose the first suggestion.
The expected behaviour is to get either new JavaClass<Integer>() or new JavaClass<>().
What I get instead is: new JavaClass<Number>().