Problem calling GetMethodID for constructor

[Lyr Lysander]

Hi there,

I am new to JNI and I try to call Java from a cobol program with JNI. The jvm is loaded properly and the FindClass works well.

If I call GetMethodID with the method-name <init> and the signature ()V I am getting the following error message:

FAILED: runJNI
java.lang.NoSuchMethodError: <init>  ()V     

Consists in specifying the method signature (for the constructor) a problem?

Many thanks in advance

Lys.

[Rob Spoor]

Apparently there is no constructor without parameters.

[Lyr Lysander]

The converning class owns definitely a parameterless constructor.

public class Display {

    public Display(){}

...
}

My first thought was, that there is something wrong with the used signature. I'm confused because of the blanks between <init> and ()V.

However, I used UFT8-Strings, which are zero-terminated, for the method name and the signature. 6 signs for the method anme and 3 signs for the signature.

The error message is confusing.

[Rob Spoor]

You provide two different strings to find a method / constructor - one for the name, one for the parameters and return type.

Can you please show us some of your JNI code? Because either there's something wrong with your arguments (possibly not terminated correctly), or it's using the wrong class.

[Lyr Lysander]

Here is the used code. As mentioned earlier, it is ugly Cobol :

 
       01 display-new-methodname PIC X(6).
       01 display-new-sig PIC X(3).

	   ...

	   move x"3c696e69743e00" to display-new-methodname.
	  * same as: move z"<init>" to display-new-methodname.
	   
	   move x"28295600" to display-new-sig .
	  * same as move z"()V" to display-new-sig .


	   call GetMethodID
             using by reference JEnv
                   by reference DisplayClass
                   by reference display-new-methodname
                   by reference display-new-sig
             returning display-new-methodId
       end-call
	   
	   ...

[Rob Spoor]

That's so ugly, I can't even read it!

But seriously, I just can't read Cobol. Perhaps someone else around can.