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javagenericscastingstruts2

How to solve this Java type safety warning?

Map session = ActionContext.getContext().getSession();
session.put("user", user);

This code generates a warning: Type safety: The method put(Object, Object) belongs to the raw type Map. References to generic type Map<K,V> should be parameterized.

Map<String, Serializable> session = (Map<String, Serializable>)ActionContext.getContext().getSession();
session.put("user", user);

This code generates a warning: Type safety: Unchecked cast from Map to Map<String,Serializable>.

The getSession method belongs to Struts2 so I can't modify it. I would like to avoid using @SuppressWarnings because other warnings can be useful.

I guess all Struts2 users in the world faced the same problem... is there an elegant solution?

Solution

  • I don't think there's any other way but @SuppressWarnings("unchecked"). I believe you can put it just above the line in question, and it will only suppress that line.

    Edit: you can also do Map<?, ?> session = ActionContext.getContext().getSession(); but I'm not sure how willing you are to do that; you won't be able to put anything into the map that way (since the compiler can't check the type of what you're putting), only read from it.