Java String replace()

replace() Syntax

The syntax of the replace() method is either

string.replace(char oldChar, char newChar)

or

string.replace(CharSequence oldText, CharSequence newText)

Here, string is an object of the String class.

replace() Parameters

To replace a single character, the replace() method takes these two parameters:

• oldChar - the character to be replaced in the string
• newChar - matching characters are replaced with this character

To replace a substring, the replace() method takes these two parameters:

• oldText - the substring to be replaced in the string
• newText - matching substrings are replaced with this string

replace() Return Value

• The replace() method returns a new string where each occurrence of the matching character/text is replaced with the new character/text.

Example 1: Java String replace() Characters

Note: If the character to be replaced is not in the string, replace() returns the original string.

Example 2: Java String replace() Substrings

Note: If the substring to be replaced is not in the string, replace() returns the original string.

It is important to note that the replace() method replaces substrings starting from the start to the end. For example,

"zzz".replace("zz", "x") // xz

The output of the above code is xz, not zx. It's because the replace() method replaced the first zz with x.

If you need to replace substrings based on a regular expression, use the Java String replaceAll() method.