Question: what version of jdk is bcel 5.1 expected to be run with?

[Claudio Corsi <cc...@progress.com>]

I have been using this tool to create a byte-code enhancement of created 
class files and I kept getting a NoSuchMethodError.

The reason that I get this is because I am running my application with 
jdk 1.3 and the method that causes this exception is the 
StringBuffer.append(StringBuffer) method.

This method does not exist within jdk 1.3 but it is part of the 
distribution of jdk 1.4.

The interesting thing about this is that I was able to build the bcel 
5.1 source using jdk 1.3!

That is why I am wondering which jdk is bcel 5.1 suppose to work with.

thanks,

--Claudio

Re: Question: what version of jdk is bcel 5.1 expected to be run with?

[Claudio Corsi <cc...@progress.com>]

Thomas Hawtin wrote:
> Claudio Corsi wrote:
> 
>>
>> I have been using this tool to create a byte-code enhancement of 
>> created class files and I kept getting a NoSuchMethodError.
>>
>> The reason that I get this is because I am running my application with 
>> jdk 1.3 and the method that causes this exception is the 
>> StringBuffer.append(StringBuffer) method.
>>
>> This method does not exist within jdk 1.3 but it is part of the 
>> distribution of jdk 1.4.
>>
>> The interesting thing about this is that I was able to build the bcel 
>> 5.1 source using jdk 1.3!
> 
> 
> For any program with code like:
> 
>     String s;
>     StringBuffer b;
>     ...
>     b.append(s);
> 
> Then using the 1.4 libraries it will compile to using 
> StringBuffer.append(String), while 1.3 will use 
> StringBuffer.append(Object) (neither of which have very nice threading 
> properties, but that's rarely significant). The standard solution is to 
> use the 1.3 libraries as the bootclasspath to javac. An easy way to do 
> that is to use JDK 1.3, but I'd suggest using 1.4 with -bootclasspath. 
> If that's out of your control you can always explicitly choose the other 
> append method:
> 
>     b.append((Object)s);
> 
> Tom Hawtin
> 

Tom,

The code in question is LineNumberTable toString method here is the code:

   public final String toString() {
     StringBuffer buf  = new StringBuffer();
     StringBuffer line = new StringBuffer();

     for(int i=0; i < line_number_table_length; i++) {
       line.append(line_number_table[i].toString());

       if(i < line_number_table_length - 1)
	line.append(", ");

       if(line.length() > 72) {
	line.append('\n');
	buf.append(line);   <-------
	line.setLength(0);
       }
     }

     buf.append(line);

     return buf.toString();
   }

The shows use that we are appending a StringBuffer and StringBuffer does 
not contain such a method within jdk 1.3. It has been introduced in jdk 1.4.

This will compile with jdk 1.4 and jdk 1.3. I have not javap the code 
but I would assume that the jdk 1.3 compiler would call the passed 
StringBuffer toString method to allow this to work.

--Claudio

> 
> 
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Re: Question: what version of jdk is bcel 5.1 expected to be run with?

[Thomas Hawtin <th...@tackline.demon.co.uk>]

Claudio Corsi wrote:
> 
> I have been using this tool to create a byte-code enhancement of created 
> class files and I kept getting a NoSuchMethodError.
> 
> The reason that I get this is because I am running my application with 
> jdk 1.3 and the method that causes this exception is the 
> StringBuffer.append(StringBuffer) method.
> 
> This method does not exist within jdk 1.3 but it is part of the 
> distribution of jdk 1.4.
> 
> The interesting thing about this is that I was able to build the bcel 
> 5.1 source using jdk 1.3!

For any program with code like:

     String s;
     StringBuffer b;
     ...
     b.append(s);

Then using the 1.4 libraries it will compile to using 
StringBuffer.append(String), while 1.3 will use 
StringBuffer.append(Object) (neither of which have very nice threading 
properties, but that's rarely significant). The standard solution is to 
use the 1.3 libraries as the bootclasspath to javac. An easy way to do 
that is to use JDK 1.3, but I'd suggest using 1.4 with -bootclasspath. 
If that's out of your control you can always explicitly choose the other 
append method:

     b.append((Object)s);

Tom Hawtin