Dan Chisholm Comprehensive Exam#1 Q#5

[Chris Gastin]

I got this answer right because I have seen this question in dan's topic exams, but I do not understand. Could someone go into a little more detail on why the answer is "E".
Thanks
Chris G.

 
class P {void m1() throws Exception {}}
class Q {
  {System.out.print("1");}
  static {System.out.print("2");}
  Q() {System.out.print("3");}
}
class R extends Q {
  {System.out.print("4"); new P().m1();}
  static {System.out.print("5");}
  R() {System.out.print("6");}
}
class S {
  public static void main(String[] args) {
    new R();
  }
}

What is the result of attempting to compile and run the program? 
a.  Prints: 251346 
b.  Prints: 256314 
c.  Prints: 123456 
d.  Prints: 142356 
e.  Compiler Error 
f.  Runtime Error 
g.  None of the Above 

[Dan Chisholm]

Originally posted by Chris Gastin:
I got this answer right because I have seen this question in dan's topic exams, but I do not understand. Could someone go into a little more detail on why the answer is "E".
Thanks
Chris G.

 
class P {void m1() throws Exception {}}
class Q {
  {System.out.print("1");}
  static {System.out.print("2");}
  Q() {System.out.print("3");}
}
class R extends Q {
  {System.out.print("4"); new P().m1();}
  static {System.out.print("5");}
  R() {System.out.print("6");}
}
class S {
  public static void main(String[] args) {
    new R();
  }
}

What is the result of attempting to compile and run the program? 
a.  Prints: 251346 
b.  Prints: 256314 
c.  Prints: 123456 
d.  Prints: 142356 
e.  Compiler Error 
f.  Runtime Error 
g.  None of the Above 

The instance initializer of class R invokes method P.m1. The throws clause of method P.m1 declares that P.m1 throws an Exception. Therefore, every constructor of class R must also have a throws clause that declares Exception.
Please see the
Java Language Specification, Section 8.6, Instance Initializers.

An instance initializer of a named class may not throw a checked exception unless that exception or one of its superclasses is explicitly declared in the throws clause of each constructor of its class and the class has at least one explicitly declared constructor. An instance initializer in an anonymous class (�15.9.5) can throw any exceptions.