Java String substring()

In this tutorial, we will learn about the Java String substring() method with the help of examples.

The Java substring() method extracts a part of the string (substring) and returns it.

Example

class Main {
  public static void main(String[] args) {
    String str1 = "java is fun";

    // extract substring from index 0 to 3
    System.out.println(str1.substring(0, 4));

  }
}

// Output: java

substring() Syntax

string.substring(int startIndex, int endIndex)

substring() Parameters

The substring() method can take a maximum of two arguments.

startIndex - the beginning index
endIndex (optional) - the ending index

substring() Return Value

The substring() method returns a substring from the given string.

The substring begins with the character at the startIndex and extends to the character at index endIndex - 1
If the endIndex is not passed, the substring begins with the character at the specified index and extends to the end of the string

Working of Java String substring() method

Note: You will get an error if

startIndex/endIndex is negative or greater than string's length
startIndex is greater than endIndex

Example 1: Java substring() With Only Start Index

class Main {
  public static void main(String[] args) {
    String str1 = "program";

    //  1st character to the last character
    System.out.println(str1.substring(0));  // program


    // 4th character to the last character
    System.out.println(str1.substring(3));  // gram
  }
}

Example 2: Java substring() With Start and End Index

class Main {
  public static void main(String[] args) {
    String str1 = "program";

    // 1st to the 7th  character
    System.out.println(str1.substring(0, 7));  // program

    // 1st to the 5th  character
    System.out.println(str1.substring(0, 5));  // progr


    // 4th to the 5th character
    System.out.println(str1.substring(3, 5));  // gr
  }
}

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