What are strings in Java?

Article by: Manish Methani

Last Updated: September 28, 2021 at 10:04am IST
3 min 19 sec

Strings, which are widely used in Java programming, are a sequence of characters. In the Java programming language, strings are objects. The Java platform provides the String class to create and manipulate strings.

How to create a string?

The most common way to create a string in Java is 

String greeting = "Hello world!"

In this case, "hello world" is a string literal also known as a sequence of characters enclosed in double-quotes. Whenever string literals are encountered, a compiler creates a String object with its value.

Most common ways to create a string in java is given below,

char[] helloArray = { 'h', 'e', 'l', 'l', 'o', '.' };

String helloString = new String(helloArray);

System.out.println(helloString);

Like any other object in Java, String is also an object. The String class in java is immutable so that once it is created a String object cannot be changed.

String Length in Java

Methods used to obtain information about an object are known as accessor methods. One of the most common accessor methods which you can use in java is the length() method. It returns the number of characters in a string. After executing the following lines of java code, len will return 40.

String baseStr = "Codzify is best to make me a super coder";

int len = baseStr.length();

How to concatenate Strings in Java?

Concatenation of strings in java is a way to combine two different strings. 

string1.concat(string2); 

This returns a new string that is string1 combined with string2 at the end of the result.

You can also use the concat() method with string literals like this

"Welcome to".concat("codzify");

You can also concatenate two strings using + operator.

"Welcome" + "to Codzify"+ "!"

which results in

Welcome to Codzify !

+ operator can also be used inside the print statements like this,

String string1 = "Java is best to give me a hike in salary ";

System.out.println("Really " + string1 + "!");

which prints

Really Java is best to give me a hike in salary!

Creating Format Strings

The string class provides a way to format the strings using the string format() method. The string format() method returns a String object rather than a PrintStream object.

The string format() method allows you to create a formatted string that you can reuse, as opposed to a one-time print statement. For example instead of 

System.out.printf("The value of float is %f" + 

"The value of integer is %d", floatVar, Intvar  );

String fs;

fs = String.format("The value of float is %f" + 
"The value of integer is %d", floatVar, Intvar
 );
System.out.println(fs);