Java String concat() Method with Examples

The concat() method in Java is used to append one string to another and returns a new combined string. It does not modify the original string since strings are immutable.

• Used to concatenate (join) two strings
• Returns a new string as the result
• Throws NullPointerException if the argument is null

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Syntax

public String concat (String s);

• Parameters:A string to be concatenated at the end of the other string.
• Return Value:Concatenated(combined) string.
• Exception:NullPointerException: When either of the string is Null.

Java String concat() Examples

There are many ways to use the concat() method in Java:

Example: Combining Two Strings with concat() Method

GeeksforGeeks

Example: Sequential Concatenation of Multiple Strings

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Note: Strings are immutable in Java, so every concatenation creates a new string object instead of modifying the existing one.

Example: Handling NullPointerException in String concat()

Output

Exception in thread "main" java.lang.NullPointerException

Example: Reversing a String Using concat() Method