The String substr() method extracts characters from a string starting at a specified position, returning the extracted part as a new string.

The String substring() method extracts characters from a string, between two positions, returning a substring, while not changing the original string.

The String toLocaleLowerCase() method converts a string to lowercase letters, using the current locale, without changing the original string.

The String toLocaleUpperCase() method converts a string to uppercase letters, using the current locale, without changing the original string.

The String toLowerCase() method converts a string to lowercase letters, without changing the original string.

The String toString() method returns a string object as a string, without changing the original string.

The String toUpperCase() method converts a string to uppercase letters, without changing the original string.

The String trim() method removes whitespace from both sides of a string, without changing the original string.

The String trimEnd() method removes whitespace from the end of a string, without changing the original string.

The String trimStart() method removes whitespace from the beginning of a string, without changing the original string.

The String valueOf() method returns the primitive value of a string, without changing the original string.