Stack Traces

When you get an exception, it will contain what is known as a "stack trace."

If a method a calls a method b which in turn calls a method c, that chain of calls forms a "stack."

If the method at the bottom, c, throws an exception that exception will contain information about that entire "call stack."

void c() {
    throw new RuntimeException();
}

void b() {
    c();
}

void a() {
    b();
}

void main() {
    a();
}

Exception in thread "main" java.lang.RuntimeException
	at Main.c(Main.java:2)
	at Main.b(Main.java:6)
	at Main.a(Main.java:10)
	at Main.main(Main.java:14)

This makes exceptions somewhat offensive to the eyes, but is extremely useful if something goes wrong in a real program. You can see exactly what method had an issue and figure out where it was called from.

Since figuring out what went wrong is a detective game, every clue helps.