Java String

In this page, we will learn about Java Strings, how to create Strings, and there various methods with the help of examples.

In java, String is a sequence of characters, for e.g. “Coding” is a string of 6 characters and it's containing a sequence of characters ' C ' , ' o ' , ' d ' , ' i ' , ' n ' and ' g '. In java, string is an immutable object which means it is constant and can cannot be changed once it has been created.

We use double quotes to represent a string in Java.

// create a string
String name = "Hello Programmer";

Here, we have created a string variable named name. The variable is initialized with the string Hello programmer.

Note: Java strings are not primitive types (like int, char, etc). Instead, all strings are objects of a predefined class named String.

And, all string variables are instances of the String class.

Creating a Java String

There are two ways to create a String in Java:

1. String literal

2. Using new keyword

1 -> String literal

In java, Strings can be created like this: Assigning a String literal to a String instance:

// create a string
String name1 = "Hello World";
String name2 = "Welcome Programmer";

Create a String in Java

Example:

class Simple{
    public static void main(String args[]){

        // create a string
        String name1 = "Java";
        String name2 = "JavaScript";
        String name3 = "PHP";

        System.out.println(name1);
        System.out.println(name2);
        System.out.println(name3);
    }
}

Output:

2 -> Using New Keyword

So far we have created strings like primitive types in Java.

Since strings in Java are objects, we can create strings using the new keyword as well.

// create a string using the new keyword
String name = new String("Hello Jaction");

In the above example, we have created a string name using the new keyword.

Create Strings in java using the new keyword

Example:

class Simple{
    public static void main(String args[]){

        // create a string using the new keyword
        String name = new String("Hello Jaction");

        System.out.println(name1);
    }
}

Output:

Java String Length

A String in Java is actually an object, which contain methods that can perform certain operations on strings. For example, the length of a string can be found with the length() method:

class Simple{
    public static void main(String args[]){

        // create a string
        String name = "Java Programming";
        System.out.println("String: " + name);

        // get the length of name
        int length = name.length();
        System.out.println("Length: " + length);
    }
}

Output:

String: Java Programming

Length: 16

In the above example, the length() method calculates the total number of characters in the string and returns it.

Join two Strings

The + operator can be used between strings to combine them. This is called concatenation:

class Simple{
    public static void main(String args[]){

        // create first string
        String str1 = "Java";
        System.out.println("First String: " + str1);

        // create second string
        String str2 = "Programmer";
        System.out.println("Second String: " + str2);

        // join str1 and str2
        System.out.println(str1 + " " + str2);
    }
}

Output:

First String: Java

Secorend String: Programmer

Full String: Java Programmer

Note: that we have added an empty text (" ") to create a space between str1 and str2 on print.

We can also use concat() method to concatenate two strings:. For example,

class Simple{
    public static void main(String args[]){

        // create first string
        String str1 = "Java";
        System.out.println("First String: " + str1);

        // create second string
        String str2 = "Programmer";
        System.out.println("Second String: " + str2);

        // join str1 and str2
        String string = str1.concat(str2);
        System.out.println("Full String: " + string);
    }
}

Output:

First String: Java

Secorend String: Programmer

Full String: Java Programmer

String Methods

Here is the list of methods supported by String class: