You can use regular expressions
// to emulate contains, [a-z] will fail on more than one character,
// so you must add .* on both sides.
if (s.matches(".*[a-z].*")) {
// Do something
}
this will check if the string contains at least one character a-z
to check if all characters are a-z use:
if ( ! s.matches(".*[^a-z].*") ) {
// Do something
}
for more information on regular expressions in java
http://docs.oracle.com/javase/6/docs/api/java/util/regex/Pattern.html