We would like to know how to create an unmodifiable map.
import java.util.Collections; import java.util.HashMap; import java.util.Map; /*www. ja va 2s . c o m*/ public class Main { public static void main(String[] args) { Map<String, String> map = getMap(); map.put("a", "b"); } public static final Map<String, String> getMap() { Map<String, String> map = new HashMap<String, String>(); map.put("x", "y"); return Collections.unmodifiableMap(map); } }
The code above generates the following result.