/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		//String key = "A-B-C-D";       // => [A, B, C, D]
		String key = "A-B-C-D-E-F"; // => [A_B, C, D, E, F]
		int keep = 3;
		String[] res = key.split("-");
		if (res.length > 4) {
			String first = String.join("-", Arrays.asList(res).subList(0, keep)); 
			List<String> lst = new ArrayList<>();
			lst.add(first);
			lst.addAll(Arrays.asList(res).subList(keep, res.length));
			res = new String[lst.size()];
			res = lst.toArray(res);
		}
		System.out.println(Arrays.toString(res));
	}
}

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