d:\java>javac TestMap.java
Note: TestMap.java uses unchecked or unsafe operations.
Note: Recomile with -Xlint:unchecked for details.
Note: TestMap.java uses unchecked or unsafe operations.
Note: Recomile with -Xlint:unchecked for details.
public void test()
{
Map m = new HashMap();
m.put(1, "ss");
System.out.println(m.get(1));
}改成: public void test()
{
Map<Integer, String> m = new HashMap<Integer, String>();
m.put(1, "ss");
System.out.println(m.get(1));
}