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Java Throwable getCause() Method with Example

Throwable Class getCause() method: Here, we are going to learn about the getCause() method of Throwable Class with its syntax and example.
Submitted by Preeti Jain, on January 06, 2020

Throwable Class getCause() method

• getCause() Method is available in java.lang package.
• getCause() Method is used to return the cause of this throwable exception and it returns null when the cause is whether non-existent or not known.
• getCause() Method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• getCause() Method does not throw an exception at the time of returning the cause of this object.

Syntax:

    public Throwable getCause();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Throwable, it returns the cause of this exception when the cause is existent or known otherwise it returns null when the cause is non-existent or not known.

Example:

// Java program to demonstrate the example 
// of Throwable getCause() method of Throwable 

public class GetCause {
    public static void main(String args[]) throws Exception {

        try {
            // calling div() method
            div(100, 0);
        } catch (ArithmeticException ex) {
            // Display the exception cause why it is
            //thrown
            System.out.println("Exception Cause:" + ex.getCause());
        }

    }

    // This method divide two numbers and will
    // throw an exception
    public static void div(int d1, int d2) throws Exception {
        try {
            int res = d1 / d2;
        } catch (ArithmeticException ex) {

            // creating an exception
            ArithmeticException ae = new ArithmeticException();

            // instantiate exception cause
            ae.initCause(ex);

            // throw an exception with its cause
            throw (ae);
        }
    }
}

Output

Exception Cause:java.lang.ArithmeticException: / by zero