Throwable toString() method in Java with Examples

Last Updated : 9 Jan, 2026

The toString() method of the java.lang.Throwable class is used to return a string representation of an exception or error. It is commonly used while printing exceptions to understand what went wrong in a program.

Below example demonstrates how Throwable.toString() provides a concise description of an exception.

Java 
import java.io.*;
public class GFG {
    public static void main(String[] args) {
        try {
            int a = 10 / 0;
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
}

Output
java.lang.ArithmeticException: / by zero

Explanation :

  • code deliberately causes an ArithmeticException by dividing 10 by 0.
  • exception is caught in the catch block.
  • e.toString() returns a string containing the exception’s class name and message.
  • output shows: java.lang.ArithmeticException: / by zero.

Syntax

public String toString()

  • Parameters: This method does not take any parameters.
  • Return Value: Returns a String representing the Throwable.

Example: This code demonstrates how to use the toString() method of the Throwable class in Java to get a readable description of an exception.

Java 
class GFG {
    public static void main(String[] args) {
        try {
            throw new NullPointerException();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
}

Output
java.lang.NullPointerException

Explanation:

  • A NullPointerException is explicitly thrown using throw new NullPointerException().
  • The exception is caught in the catch block as a generic Exception.
  • e.toString() is called to get a string representation of the exception.
  • Since no custom message is provided, it outputs the class name: java.lang.NullPointerExceptio
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