Java Strings Concatenation

String concatenation refers to the process of joining two or more strings together.

Using the + Operator

The + operator can be used to merge strings. This is called concatenation:

Example

String carMake = "Toyota";
String carModel = "Supra";
System.out.println(carMake + " " + carModel);

String carMake = "Toyota";

String carModel = "Supra";

System.out.println(carMake + " " + carModel);

Note that we included an empty string (” “) to create a space between carMake and carModel when printing.

Using the concat() Method

You can also use the concat() method to concatenate two strings:

Example

String carMake = "Toyota ";
String carModel = "Supra";
System.out.println(carMake.concat(carModel));

String carMake = "Toyota ";

String carModel = "Supra";

System.out.println(carMake.concat(carModel));

Additional Information

String concatenation is useful in various scenarios, such as generating dynamic messages or combining user input.

You can also concatenate multiple strings in a single statement:

Example

String brand = "Toyota";
String model = "Supra";
String year = "2025";
System.out.println(brand + " " + model + " " + year);

String brand = "Toyota";

String model = "Supra";

String year = "2025";

System.out.println(brand + " " + model + " " + year);

This creates a full sentence combining all three strings with spaces in between.

Efficiency Note

While concatenation using + is simple, for larger applications or loops, StringBuilder or StringBuffer is recommended for better performance:

Example

StringBuilder carDetails = new StringBuilder();
carDetails.append("Toyota");
carDetails.append(" ");
carDetails.append("Supra");
System.out.println(carDetails.toString());

StringBuilder carDetails = new StringBuilder();

carDetails.append("Toyota");

carDetails.append(" ");

carDetails.append("Supra");

System.out.println(carDetails.toString());