JAVA EE: Java Tutorial : Java Exception handling (Exception propagation)

Tuesday, 28 June 2016

Java Tutorial : Java Exception handling (Exception propagation)

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Java Tutorial : Java Exception handling (Exception propagation)

ExceptionPropagationDemo.java

public class ExceptionPropagationDemo
{

    public static void main(String[] args)
    {
        ExceptionPropagationDemo exceptionPropagationDemo = new ExceptionPropagationDemo();
        try
        {
            exceptionPropagationDemo.method1();
        }
        catch(Exception exe)
        {
            exe.printStackTrace();
            System.out.println("Exception is handled in main method.");
        }
        System.out.println("Normal flow...");
    }

    public void method1()
    {
        System.out.println("method1() is called.");
        method2();
    }

    public void method2()
    {
        System.out.println("method2() is called.");
        method3();
    }

    public void method3()
    {
        System.out.println("method3() is called.");
        String str = null;
        System.out.println(str.length());
    }

}

Output

method1() is called.
method2() is called.
method3() is called.
java.lang.NullPointerException
    at ExceptionPropagationDemo.method3(ExceptionPropagationDemo.java:35)
    at ExceptionPropagationDemo.method2(ExceptionPropagationDemo.java:28)
    at ExceptionPropagationDemo.method1(ExceptionPropagationDemo.java:22)
    at ExceptionPropagationDemo.main(ExceptionPropagationDemo.java:9)
Exception is handled in main method.