Java – String substring() Method example

Technique substring() restores another string that is a substring of given string. Java String substring() technique is utilized to get the substring of a given string dependent on the passed lists. There are two variations of this technique. In this guide, we will perceive how to utilize this technique with the assistance of models.

String substring() method variants

There are two ways we can use the substring() method –

1. When we pass only the starting index:

String substring(int beginIndex)

Returns the substring beginning from the predefined file i.e beginIndex and stretches out to the character present toward the finish of the string. For instance – “Chaitanya”.substring(2) would return “aitanya”. The beginIndex is comprehensive, that is the reason the character present at the record 2 is remembered for the substring. This strategy tosses IndexOutOfBoundsException If the beginIndex is under zero or more prominent than the length of String (beginIndex<0||> length of String).

2. When we pass both the indexes, starting index and end index:

String substring(int beginIndex, int endIndex)

Returns a new string that is a substring of this string. The substring begins at the specified beginIndex and extends to the character at index endIndex – 1. Thus the length of the substring is endIndex-beginIndex. In other words you can say that beginIndex is inclusive and endIndex is exclusive while getting the substring.

For example – "Chaitanya".substring(2,5) would return "ait". It throws IndexOutOfBoundsException If the beginIndex is less than zero OR beginIndex > endIndex OR endIndex is greater than the length of String.

Java String substring() example

Now that we understand the basics of substring() method, lets take an example to understand the usage of this method.

Here we have a string str and we are finding out the substring of this string using the substring() method.

public class SubStringExample{
   public static void main(String args[]) {
       String str= new String("quick brown fox jumps over the lazy dog");
       System.out.println("Substring starting from index 15:");
       System.out.println("Substring starting from index 15 and ending at 20:");
       System.out.println(str.substring(15, 20));


Substring starting from index 15:
 jumps over the lazy dog
Substring starting from index 15 and ending at 20:


Numerous people groups are befuddled that the returned substring in the subsequent technique call should be hops rather than hop, this is on the grounds that the returned substring length should be endIndex-beginIndex, in our model beginIndex is 15 and endIndex is 20, along these lines the length of returned substring should be 20-15 = 5. The right answer is ” hop” on the grounds that there is a space before the bounce so the length of substring ” hop” is 5 (counting the space).

To additionally dodge disarray, I am sharing an another illustration of this strategy which is anything but difficult to follow.

Another example of String substring() method

public class JavaExample{
   public static void main(String args[]) {
	String mystring = new String("Lets Learn Java");
	/* The index starts with 0, similar to what we see in the arrays
	 * The character at index 0 is s and index 1 is u, since the beginIndex
	 * is inclusive, the substring is starting with char 'u'
	/* When we pass both beginIndex and endIndex, the length of returned
	 * substring is always endIndex - beginIndex which is 3-1 =2 in this example
	 * Point to note is that unlike beginIndex, the endIndex is exclusive, that is 
	 * why char at index 1 is present in substring while the character at index 3 
	 * is not present.




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