regex - using regular expression in Java

Question

i need to check a string that should contain only ABCDEFG characters, in any sequence and with only 7 characters. Please let me know the correct way of using regular expression.

as corrently i am using

String abs = "ABPID";
if(!Pattern.matches("[[ABCDEFG]", abs))
System.out.println("Error");

i am using the following code which works when i use the String abcdefg but for other cases it fails. please help me out.

Answer 1

Exactly 7 characters

"^[ABCDEFG]{7}$"

1 to 7 characters

"^[ABCDEFG]{1,7}$"