String Methods for Character Extraction in Java

Java Tutorial String Methods in Java

String Searching Methods in Java

Permutations of given String - GeeksforGeeks

Java - Print all permutations of a specified string

How many permutations of the letters ABCDEFG containa) the st... | Filo

String Concatenation

Java String concat() Method with Examples - GeeksforGeeks

Java - Concatenate a string to the end of another string