Java PatternSyntaxException Class getIndex() Method with Examples

Java PatternSyntaxException Class is defined under the java.util.regex package and it depicts unchecked exception that signifies syntax error in a regular expression pattern. This class can be declared using the below syntax,

public class PatternSyntaxException extends IllegalArgumentException

PatternSyntaxException::getIndex()

This method is used to retrieve the index of the error which is thrown as an exception. The syntax is given below,

Syntax:

public int getIndex()

Returns: It returns a non-negative integer: The index in the pattern of the error is -1 if the index cannot be retrieved

Example 1: In this example, the error is at the index 0 in the pattern. This is because of the unclosed character.  

Index: 0
Message: Unclosed character class near index 0
[
^

Example 2: In this example, getIndex() method returns -1. This is because of illegal repetition the index cannot be retrieved.