initializing static Map of ArrayList

I want to define a static Map of ArrayList to include bunch of pairs of [key, ArrayList object]'s.

There is a lot to be added to these pairs during time, but they're fixed during each execution. So the best approach is initialization while defining the map of arrayList.

I can do this by a static method including:

arrayList.add("value1"), arrayList.add("value2"), arrayList.add("value3"), ... 

and then:

map.put("key", arrayList) 

However, these have to be repeated for each pair of [key, ArrayList].

I tried ImmutableMap, but got this error:

Exception in thread "main" java.lang.ExceptionInInitializerError Caused by: java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayList at bugTriaging.Constants.<clinit>(Constants.java:11) 

Here's my code:

package package1; import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.Map; import com.google.common.collect.ImmutableMap; public class Constants { static final Map<String, ArrayList<String>> map1 = ImmutableMap.<String, ArrayList<String>>builder() .put("key1", (ArrayList<String>) Arrays.asList("value1", "value2", "value3")) .put("key2", (ArrayList<String>) Arrays.asList("value4", "value5", "value6", "value7")) .put("key3", (ArrayList<String>) Arrays.asList("value8", "value9", "value10", "value11", "value12", "value13")) .build(); public static void main(String[] args) { System.out.println("Started ..."); } } 

I have played with static and final values, but couldn't run it.

Finally, I could run this code:

 @SuppressWarnings("serial") //to avoid the warning. public static HashMap<String, ArrayList<String>> map2 = new HashMap<String, ArrayList<String>>() {{ put("key1", new ArrayList<String>() {{ add("value1"); add("value2"); }}); put("key2", new ArrayList<String>() {{ add("value3"); add("value4"); add("value5"); }}); put("key3", new ArrayList<String>() {{ add("value6"); add("value7"); add("value8"); }}); }}; 

Here are my questions:

1- What is the problem of ImmutableMap in my first approach?

2- With my solution, I get warnings ("The serializable class does not declare a static final serialVersionUID field of type long"). Is adding @SuppressWarnings("serial") the right way of getting rid of warnings or there is a better way?