Review

Checks the return value of Map.put() to check whether the key was set before. If the Map allows null values, this usage breaks.

Use Map.containsKey() to check whether a key is set.

• missing/condition/value_or_state

mubench/examples/survey/Maps.java

mapMayContainNull(Map)

class Maps {
	void mapMayContainNull(Map<String, Object> m) {
		if (m.put("foo", new Object()) != null) {
			// "foo" was set before
		} else {
			// "foo" was not set before (or set to null!)
		}
	}

}