From leonid.kuskov at oracle.com  Thu Mar 12 23:43:10 2015
From: leonid.kuskov at oracle.com (Leonid Kuskov)
Date: Thu, 12 Mar 2015 16:43:10 -0700
Subject: the main method in an interface
Message-ID: <5502248E.8040101@oracle.com>

Hello Alex,

JVMS and JLS don't take into account that the main method can be in an 
interface.
Assertion jvms-5.5-110-F states "If C is a class, its designation as the 
initial class at Java Virtual Machine startup".
But C may be an interface also. HotSpot initializes such interface 
successfully.
$ cat Intf.jasm
public interface Intf
         version 52:0
{

public static Method main:"([Ljava/lang/String;)V"
         stack 2 locals 1
{
                 getstatic       Field 
java/lang/System.out:"Ljava/io/PrintStream;";
                 ldc     String "Hello, world!";
                 invokevirtual   Method 
java/io/PrintStream.println:"(Ljava/lang/String;)V";
                 return;

}

static Method "<clinit>":"()V"
         stack 2 locals 0
{
                 getstatic       Field 
java/lang/System.out:"Ljava/io/PrintStream;";
                 ldc     String "initialized";
                 invokevirtual   Method 
java/io/PrintStream.println:"(Ljava/lang/String;)V";
                 return;
}

} // end Class Intf

Output:
$ java Intf
initialized
Hello, world!

Looks like JLS and JVMS don't take into account interfaces with the main 
method in other places too (JVMS 5.2, JLS 12.1, maybe more).

And second question is:

Umbrella assertion jvms-5.5-110 includes assertions about the ways how a 
class can be initialized (execution of 
new/getstatic/putstatic/invokestatic, invocation of MethodHandle etc).
Each of them, except invocation of reflective methods, clarifies that a 
class will be initialized only if it hasn't been initialized already.
Why there is no such clarification for reflection (jvms-5.5-110-C)?


Thanks,
Leonid

From alex.buckley at oracle.com  Fri Mar 13 21:12:40 2015
From: alex.buckley at oracle.com (Alex Buckley)
Date: Fri, 13 Mar 2015 14:12:40 -0700
Subject: the main method in an interface
In-Reply-To: <5502248E.8040101@oracle.com>
References: <5502248E.8040101@oracle.com>
Message-ID: <550352C8.2080405@oracle.com>

Hi Leonid,

On 3/12/2015 4:43 PM, Leonid Kuskov wrote:
> Hello Alex,
>
> JVMS and JLS don't take into account that the main method can be in an
> interface.
> Assertion jvms-5.5-110-F states "If C is a class, its designation as the
> initial class at Java Virtual Machine startup".
> But C may be an interface also. HotSpot initializes such interface
> successfully.
> $ cat Intf.jasm
> public interface Intf
>          version 52:0
> {
>
> public static Method main:"([Ljava/lang/String;)V"
>          stack 2 locals 1
> {
>                  getstatic       Field
> java/lang/System.out:"Ljava/io/PrintStream;";
>                  ldc     String "Hello, world!";
>                  invokevirtual   Method
> java/io/PrintStream.println:"(Ljava/lang/String;)V";
>                  return;
>
> }
>
> static Method "<clinit>":"()V"
>          stack 2 locals 0
> {
>                  getstatic       Field
> java/lang/System.out:"Ljava/io/PrintStream;";
>                  ldc     String "initialized";
>                  invokevirtual   Method
> java/io/PrintStream.println:"(Ljava/lang/String;)V";
>                  return;
> }
>
> } // end Class Intf
>
> Output:
> $ java Intf
> initialized
> Hello, world!
>
> Looks like JLS and JVMS don't take into account interfaces with the main
> method in other places too (JVMS 5.2, JLS 12.1, maybe more).

Thanks for spotting that we really support an initial class _or 
interface_. I confirmed with Brian Goetz that this is intentional, and 
have filed https://bugs.openjdk.java.net/browse/JDK-8075167.

> And second question is:
>
> Umbrella assertion jvms-5.5-110 includes assertions about the ways how a
> class can be initialized (execution of
> new/getstatic/putstatic/invokestatic, invocation of MethodHandle etc).
> Each of them, except invocation of reflective methods, clarifies that a
> class will be initialized only if it hasn't been initialized already.
> Why there is no such clarification for reflection (jvms-5.5-110-C)?

There are six clauses under the umbrella "only as a result of" 
assertion; only the first says "if it has not been initialized already." 
That's both redundant (since the initialization algorithm itself doesn't 
reinitialize) and potentially confusing (because it can be read as 
implying that initialization always succeeds). I have filed 
https://bugs.openjdk.java.net/browse/JDK-8075168. I think the question 
about why the reflective clause doesn't say it is now moot (and in any 
case the JVMS tries to make very few commitments about the behavior of 
reflection).

Alex

From thank-the-lord at gmx.de  Sat Mar 14 17:31:01 2015
From: thank-the-lord at gmx.de (thank-the-lord at gmx.de)
Date: Sat, 14 Mar 2015 18:31:01 +0100
Subject: JVMS8 RuntimeVisibleTypeAnnotations Attribute
Message-ID: <trinity-8a5cb855-12cd-44d8-9e96-2f998f0a328c-1426354261754@3capp-gmx-bs40>

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From johnny.gerard at hotmail.com  Sun Mar 29 20:30:21 2015
From: johnny.gerard at hotmail.com (=?UTF-8?B?Sm9obm55IEfDqXJhcmQ=?=)
Date: Sun, 29 Mar 2015 22:30:21 +0200
Subject: switch statement definition
Message-ID: <BLU436-SMTP13549BB5CD836FBF9541D31F2F60@phx.gbl>

Hi,

I find the switch statement syntactic definition pretty unclear.

I'd like to know if the following definition is correct and could be a 
new definition for the specification :

*SwitchStatement*:
     switch ( Expression ) SwitchBlock

*SwitchBlock*:
     { /{/SwitchLabel/}/ }
     { SwitchLabels BlockStatements /{/SwitchBlockStatement/}/ }


*SwitchBlockStatement*:
     SwitchLabel
     BlockStatement

So, to be clear : I replaced *SwitchBlock* by a new one and**created the 
non terminal symbol *SwitchBlockStatement*.
This new *SwitchStatement *is not using the *SwitchBlockStatementGroup* 
symbol.

I hope this is clear enough.

Johnny G?rard


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