What does signify in a Java exception?

Question

What does signify in a Java exception?

For example:

BlahBlahException...

at java.io.FileInputStream.(FileInput         


        

Answer 1

That the exception is thrown in the construction of the object, there are two options:

• in the constructor
• while initializing variables

Check out this demo I wrote: http://ideone.com/Mm5w5

---

class Main
{
        public static void main (String[] args) throws java.lang.Exception
        {
                try
                { new Test(); } catch (Exception e) { e.printStackTrace(); }

                try
                { new Test2(); } catch (Exception e) { e.printStackTrace(); }

                try
                { new Test3(); } catch (Exception e) { e.printStackTrace(); }


        }

        static class Test
        {
                Object obj = getObject();
                Object getObject()
                { throw new RuntimeException("getObject"); }
        }

        static class Test2
        {
                Test2()
                {
                        throw new RuntimeException("constructor");
                }
        }

        static class Test3
        {
                Object obj1 = null;
                String str = obj1.toString();
        }
}

Produces:

java.lang.RuntimeException: getObject
    at Main$Test.getObject(Main.java:24)
    at Main$Test.(Main.java:22)
    at Main.main(Main.java:9)
java.lang.RuntimeException: constructor
    at Main$Test2.(Main.java:31)
    at Main.main(Main.java:12)
java.lang.NullPointerException
    at Main$Test3.(Main.java:38)
    at Main.main(Main.java:15)