I have this small piece of code
String[] words = {\"{apf\",\"hum_\",\"dkoe\",\"12f\"}; for(String s:words) { if(s.matches(\"[a-z]\")) { Syste
[a-z] matches a single char between a and z. So, if your string was just "d", for example, then it would have matched and been printed out.
[a-z]
"d"
You need to change your regex to [a-z]+ to match one or more chars.
[a-z]+