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  1. import java.util.List;
  2.  
  3. class Ideone {
  4.  
  5. 	static abstract class A {
  6.  
  7. 		abstract List m1();
  8.  
  9. 		abstract List<List> m2();
  10.  
  11. 	}
  12.  
  13. 	static class B extends A {
  14.  
  15. 		List<?> m1() {
  16. 			return null;
  17. 		}
  18.  
  19. 		List<List<?>> m2() {
  20. 			return null;
  21. 		}
  22.  
  23. 	}
  24.  
  25. 	public static void main(String[] args) {
  26. 		System.out.println("Yo.");
  27. 	}
  28.  
  29. }
  30.  
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin 
Standard input is empty
compilation info 
Main.java:13: error: B is not abstract and does not override abstract method m2() in A
	static class B extends A {
	       ^
Main.java:19: error: m2() in B cannot override m2() in A
		List<List<?>> m2() {
		              ^
  return type List<List<?>> is not compatible with List<List>
2 errors
stdout 
Standard output is empty
https://ideone.com/DF43JK
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
public

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