The `substring()` method in Java returns a *portion of a string* and is used to get substrings in java.

There are two variants for the `substring()` method implementation​ in Java. 


# Variant 1
We specify a start index and the returned substring includes​ characters starting from the specified start index, of the input string, until the end of the string. 

```java
stringName.substring(int startIndex)
``` 
A visualization​ of this is shown below:

class HelloWorld {
    public static void main( String args[] ) {
      String str="edpresso"; 
      System.out.println( str.substring(2) );
    }
}

# Variant 2
We specify the start index *and* the end index, ​and the returned substring includes characters including and between the specified indexes. The character at the start index is included, but the character at the end index is *not* included while getting the substring. So, the characters in the extracted substring begin from *start index* to *end index-1*
```java
stringName.substring(int startIndex, int endIndex)
``` 
A visualization​ of this is shown below:

class HelloWorld {
    public static void main( String args[] ) {
      String str="edpresso"; 
      System.out.println( str.substring(2,7) );
    }
}


>**Note:** `substring()` method does not change the original string.

# Application of substrings 
Substring extraction is useful for prefix and suffix extraction. For example, it is helpful in extracting the family name from a name.

How to get a substring in Java

Java's `substring()` method returns string portions based on start and optional end indices without altering the original string.