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Bug 333665

Summary:	[DOM] Wrong binding generated for Array.clone() method
Product:	[Eclipse Project] JDT	Reporter:	arlindolima
Component:	Core	Assignee:	Jay Arthanareeswaran <jarthana>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	major
Priority:	P3	CC:	jarthana, manoj.palat, markus.kell.r, noopur_gupta, Olivier_Thomann, srikanth_sankaran
Version:	3.7
Target Milestone:	---
Hardware:	All
OS:	All
Whiteboard:	stalebug

Description arlindolima

2011-01-06 11:05:04 EST

Build Identifier: M20100909-0800

The clone() method in an array generates a binding to the Object.clone() method. However, it is stated in JLS3 §10.7:

"The members of an array type are all of the following:
. . . The public method clone, which overrides the method of the same name in class Object and throws no checked exceptions. . . . All the members inherited from class Object; the only method of Object that is not inherited is its clone method."

This means, the binding should be targeted to the Array implementation of clone().

Reproducible: Always

Steps to Reproduce:
1. Check the binding of the following statement:

"Integer[] a = ( new Integer[2]).clone();"

Comment 1 Olivier Thomann

2011-01-06 11:30:25 EST

The declaring class should indeed be Integer[] as shown in the disassembled code:
  // Method descriptor #15 ([Ljava/lang/String;)V
  // Stack: 2, Locals: 2
  public static void main(String[] args);
     0  iconst_2
     1  anewarray Integer [16]
     4  invokevirtual Integer[].clone() : Object [18]
     7  checkcast Integer[] [19]
    10  astore_1 [a]
    11  getstatic System.out : PrintStream [24]
    14  aload_1 [a]
    15  invokevirtual PrintStream.println(Object) : void [30]
    18  return

Investigating what binding we get in this case.

Comment 2 Olivier Thomann

2011-01-06 13:31:41 EST

Note that this is true only if the source option is 1.5 or above. In 1.4 or below, the code doesn't compile.

Comment 3 arlindolima

2011-01-06 15:46:02 EST

Related: An array ITypeBinding's DECLARED_FIELDS and DECLARED_METHODS shouldn't be empty. It should have one filed (length) and one method (clone).

Comment 4 Olivier Thomann

2011-01-07 09:19:42 EST

(In reply to comment #3)
> Related: An array ITypeBinding's DECLARED_FIELDS and DECLARED_METHODS shouldn't
> be empty. It should have one filed (length) and one method (clone).
I have some problem with this as an array ITypeBinding has no declaring type declaration as is. So I don't see how we can have declared fields or methods.

Srikanth, any thoughts on this ?

Comment 5 Srikanth Sankaran

2011-01-10 02:17:16 EST

(In reply to comment #4)
> (In reply to comment #3)
> > Related: An array ITypeBinding's DECLARED_FIELDS and DECLARED_METHODS shouldn't
> > be empty. It should have one filed (length) and one method (clone).
> I have some problem with this as an array ITypeBinding has no declaring type
> declaration as is. So I don't see how we can have declared fields or methods.
> 
> Srikanth, any thoughts on this ?

This looks similar to bug 330328. Right now the javadoc on ITypeBinding
says:  "an array type - array types are referenced but not explicitly
declared". Perhaps this could be expanded upon a bit.

Comment 6 Olivier Thomann

2011-08-25 09:10:50 EDT

(In reply to comment #5)
> This looks similar to bug 330328. Right now the javadoc on ITypeBinding
> says:  "an array type - array types are referenced but not explicitly
> declared". Perhaps this could be expanded upon a bit.
What do you suggest ?

Comment 7 Markus Keller

2014-07-24 09:37:27 EDT

(In reply to Olivier Thomann from comment #6)
> What do you suggest ?

See comment 3.

(In reply to Olivier Thomann from comment #4)
> I have some problem with this as an array ITypeBinding has no declaring type
> declaration as is. So I don't see how we can have declared fields or methods.

We already have a type binding for the array type, so it totally makes sense to give it the field and method that are declared in JLS8 10.7. For a type/member to exist in the model, it doesn't have to be declared in a class file.

In this snippet, the IMethodBinding for "add" also has a non-null getDeclaringClass(), whose getDeclaredMethods() includes this method again: 

        List<String> al= new ArrayList<>();
        al.add("Hi");

And all that although there's no declaration for type List<String> nor for its method with signature "boolean add(String)".

Comment 8 Markus Keller

2014-07-24 09:41:36 EDT

This should only be implemented in a new AST#apiLevel(), since existing clients may rely on the "getDeclaringClass() == null" check to find out whether a "length" field is from an array type.

Comment 9 Jay Arthanareeswaran

2015-05-12 02:57:13 EDT

Sorry, this needs to be moved out of 4.5.

Comment 10 Jay Arthanareeswaran

2016-04-05 04:34:05 EDT

No progress yet and unlikely to get time during 4.6. Moving out.

Comment 11 Manoj N Palat

2018-05-21 06:07:06 EDT

Bulk move out of 4.8

Comment 12 Eclipse Genie

2020-05-20 11:59:21 EDT

This bug hasn't had any activity in quite some time. Maybe the problem got resolved, was a duplicate of something else, or became less pressing for some reason - or maybe it's still relevant but just hasn't been looked at yet. As such, we're closing this bug.

If you have further information on the current state of the bug, please add it and reopen this bug. The information can be, for example, that the problem still occurs, that you still want the feature, that more information is needed, or that the bug is (for whatever reason) no longer relevant.

--
The automated Eclipse Genie.