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Article:
  Generic Types, Part 1
Subject:   Dangerous approximation
Date:   2005-05-05 13:17:08
From:   lordpixel
In the article we see this statement:


" A List<?> is effectively read-only since the compiler does not allow us to invoke methods like add( ), set(), and addAll( )."


That's an attractive trap people fall into with List<?>. The trouble is it's not really true. Consider the List.clear() method. It takes no parameters and thus you can call it on a List<?>.


If you want a truly read-only list, you still need to use Collections.unmodifiableList()
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  • Dangerous approximation
    2007-05-17 05:42:31  y2mehul [Reply | View]

    In fact, add(null) will be allowed by the compiler.