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Java String concat Method

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The Java String concat Method is one of the String Methods, which is to join the user-specified string to the end of the existing string.

In this article, we will show how to use the String concat method in Java Programming language with an example.

Java String concat Method syntax

The basic syntax of the string.concat in Java Programming language is as shown below.

public String concat(String str); // It will return String 

//In order to use in the program
String_Object.concat(String str)
  • String_Object: Please specify the valid String Object.
  • str: Please specify the String that you want to join to the end of the String_Object.

Return Value

The string.concat Function will join one or more strings and return a new string.

Java String concat Method Example

The Java string concat method is useful for joining one or more strings. This program will help to understand the string.concat method and its alternative approach.

package StringFunctions;

public class ConcatMethod {
	public static void main(String[] args) {
		String str1 = "Learn";
		String str2 = " Java Programming";
		String str3 = " at tutorialgateway.org";
		
		String str4 = str1.concat(" JAVA");
		String str5 = str1.concat(str2);
		String str6 = str1.concat(str2).concat(str3);
		
		String str7 = str1 + str2;
		
		System.out.println(str4);
		System.out.println(str5);
		System.out.println(str6);
		System.out.println(str7);
	}
}

OUTPUT

Java String concat Method 1

ANALYSIS

First, we declared three String variables str1, str2, str3, and assigned some random data using the following statements.

String str1 = "Learn";
String str2 = " Java Programming";
String str3 = " at tutorialgateway.org";

From the above statements, you can observe that we are using extra white spaces before the string data to provide nice and clean spaces while displaying the data.

Next, we used the String data directly inside the Java string.Concat() function.

String str4 = str1.concat(" JAVA");

The following statement will concat str1 and str2. It means str2 will add to the end of str1.

String str5 = str1.concat(str2);

The following statement will concat str1, str2, and str3. It means, first str2 will be added to the end of str1, and then str3 will be added to the end of str2.

String str6 = str1.concat(str2).concat(str3);

In Java Programming Language, We can achieve the same (concatenation of strings) using Arithmetic Operator ‘+’. The following statement will show you the same.

String str7 = str1 + str2;

The following System.out.println statements will print the output.

System.out.println(str4);
System.out.println(str5);
System.out.println(str6);
System.out.println(str7);