Calling c method from java

Hi,
I am new to JNI. I want to call a C function from java, where my C function name is
UINT8 abc(UINT8 feature, UINT8* in_value, UINT32 serialNo, UINT8 * out_value)
where,
typedef unsigned char UINT8;
typedef unsigned int UINT32;
My question is what should be the prototype defination in java and what has to be changed in C code to make it work?

After adding the native keyword to your Java method, compile with javac and run javah on the class name. For example:
package my.stuff;
public class MyClass
   public native void myMethod(char param1, int param2);
}javac ./my/stuff/MyClass.java
javah my.stuff.MyClass
This generates my_stuff_MyClass.h, which has the function prototype for your method. Inside the implementation of the function, you can call your C function.
Here is the contents for my_stuff_MyClass.h:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class my_stuff_MyClass */
#ifndef _Included_my_stuff_MyClass
#define _Included_my_stuff_MyClass
#ifdef __cplusplus
extern "C" {
#endif
* Class:     my_stuff_MyClass
* Method:    myMethod
* Signature: (CI)V
JNIEXPORT void JNICALL Java_my_stuff_MyClass_myMethod
(JNIEnv *, jobject, jchar, jint);
#ifdef __cplusplus
#endif
#endif

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I read that :
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}Is this the correct way to do it.
Any suggestion would be a great help to me

tryit wrote:
I need to call C++ method from Java.Not possible.
JNI uses C methods.
Is this the correct way to do it.Same way you would do it in any C/C++ method (not java)
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Common idiom for the pointer in the above is to pass it back and forth to your java code as a java long. You cast it it and from your class pointer. Provide an explicit java method to free it when done. Besides providing the explicit method also implement a finalizer to free it as well (however that is a fail safe and should not be relied upon.)

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Hi this is sri,
I have one doubt on Java Applets "how to call the javascript method from java Applet".Can u give me the complete sample code for one program(both java applet file and html file also)because i can easily understand the programming flow.
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It's an extremely important skill to learn how to search the web. Not only will it increase your research and development talents, it will also save you from asking questions that have already been answered numerous times before. By doing a little research before you ask a question, you'll show that you're willing to work and learn without needing to have your hand held the entire time; a quality that is seemingly rare but much appreciated by the volunteers who are willing to help you.
If you've done the research, found nothing useful, and decide to post your question, it's a great idea to tell us that you've already searched (and what methodologies you used to do your research). That way, we don't refer you back to something you've already seen.
To get you started, here's a link...
http://www.google.com/search?q=call+java+from+javascript

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I'm trying to get set up to call a C++ method from a Java app on a SUSE Linux box. I follow the steps of the "Hello World" baby example in Beth Stearns's tutorial, "Integrating Native Code and Java Programs", but I get the following error message:
Exception in thread "main" java.lang.UnsatisfiedLinkError: /users/dmizell/testIF/libhello.so: /users/dmizell/testIF/libhello.so: invalid ELF header (Possible cause: endianness mismatch)
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
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at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1703)
at java.lang.Runtime.loadLibrary0(Runtime.java:823)
at java.lang.System.loadLibrary(System.java:1028)
at HelloWorld.<clinit>(HW.java:7)
at Main.main(Main.java:5)
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Your library is compiled in a way which is incompatible with the VM you are using.
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When I call a C++ DLL method from Java using JNI, do I instantiate it like an object method or is it called as a static method ?
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The question is not specific enough.
Methods in C/C++ can be qualified with the following forms:
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Data in C/C++ can always become corrupt and in the vast (all?) cases it is because something is wrong in the C/C++ code. Like a pointer that is not initialized, or a pointer used after it is free'd. Or writing past the end of a buffer, or writing before the beginning of a buffer.

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Hello,
May know how to submit a button autoamtically on onload of page with clicking a welcome alert box. the submit button has managed button too to show a message on console using SOP.
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<?xml version='1.0' encoding='UTF-8'?>
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xmlns:f="http://java.sun.com/jsf/core"
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xmlns:af="http://xmlns.oracle.com/adf/faces/rich">
<jsp:directive.page contentType="text/html;charset=UTF-8"/>
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</af:form>
</af:document>
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</jsp:root>
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well if someone had been nice enough to provide me
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muddle, no need to be rude is there!I'm not rude. And you also wouldn't have gotten into the muddle if you searched yourself. This site provides many very good tutorials about all kinds of stuff.
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Curious thing while calling a procedure from Java !...

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### Error ###
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Please provide your Java and OS versions, the JDBC jar file and the Oracle DB version being used when you post.
>
I was expecting a big big exception
>
Then why do you have an empty exception block? That just makes it disappear so you won't see one if it happens.
And your code has
cs.registerOutParameter(4,OracleTypes.VARCHAR);
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Remove the 'setSTring' for the OUT parameter.
Then as malcollmmc already said
>
Sounds like the PL/SQL is returning "Error" as the 4th parameter of the call
>
The actual value returned by PL/SQL is strictly determined by the PL/SQL code and Java and JDBC are not involved.
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Hello.
Check my wiki article:
http://wiki.sdn.sap.com/wiki/display/stage/SapNetweaverProcessIntegration.CallEjb3.0methodfromJavaclassmappingPI7.1
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Any examples, please point
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There's a JNI forum here that may be a better place for this question; though given the general nature of the question, I suspect that they'll refer you to a tutorial. good luck.

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Hello all,
I want to call BlockInput method from User32.dll. My source code looks something like this:
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Exception in thread "main"
Can someone provide me a solution for this?
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can't do
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Here's one I wipped up in 10 minutes... Cool!
package forums;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import krc.utilz.io.Filez;
import java.io.FileNotFoundException;
class FileDisplayer extends JFrame
private static final long serialVersionUID = 0L;
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public static String read(Reader in) {
    try {
      StringBuffer out = new StringBuffer();
      try {
        char[] bfr = new char[BFRSIZE];
        int n = 0;
        while( (n=in.read(bfr,0,BFRSIZE)) > 0 ) {
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}Edited by: corlettk on Dec 16, 2007 1:01 PM - dang [code [/tags][

Calling c method from java

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