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  1.  
  2. /* Name of the class has to be "Main" only if the class is public. */
  3. public class Main
  4. {
  5. 	public static class MyClass {
  6. 		public MyClass() {
  7. 			System.out.println("MyClass default constructor");
  8. 		}
  9. 	}
  10.  
  11. 	public static class MySubClass extends MyClass {
  12. 		public MySubClass() {
  13. 			super();
  14. 			System.out.println("MySubClass default constructor");
  15. 		}
  16. 	}
  17.  
  18. 	public static class Factory<T extends MyClass> {
  19. 		public T create() {
  20. 			final T t = new T();
  21. 			return t;
  22. 		}
  23.  
  24. 		public T create(final Class<? extends T> clazz) throws Exception {
  25. 			final T t = clazz.newInstance();
  26. 			return t;
  27. 		}
  28. 	}
  29.  
  30. 	public static void main(String[] args) throws Exception {
  31. 		final Factory<MySubClass> factory = new Factory<MySubClass>();
  32.  
  33. 		final MySubClass msc = factory.create();
  34. 		// final MySubClass msc = factory.create(MySubClass.class);
  35.  
  36. 		System.out.println("Created instance: " + msc);
  37. 	}
  38. }
Compilation error #stdin compilation error #stdout 0.12s 320576KB
comments (?)
stdin
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Standard input is empty
compilation info 
Main.java:20: error: unexpected type
			final T t = new T();
			                ^
  required: class
  found:    type parameter T
  where T is a type-variable:
    T extends MyClass declared in class Factory
1 error
stdout
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Standard output is empty
https://ideone.com/th18eh
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
public

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