aaa.java
class aaa
{ public static void main(String s[])
{ bbb a;
System.out.println("Start");
a = new bbb();
System.out.println("Before xx");
a.xx();
System.out.println("After xx");
}
}
class bbb
{ public native void xx();
public bbb()
{
System.out.println("in bbb");
System.loadLibrary("sss");
}
}
sss.c
#include <windows.h>
void *Java_bbb_xx_stub(void * p)
{ MessageBox(0,"Hi","Hi",0);
return p;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
The Files to be included in the Project are
sss.c
user32.lib
aaa.java
class aaa
{ public static void main(String s[])
{ bbb a;
a = new bbb();
a.xx();
System.out.println("After xx");
}
}
class bbb
{ public native void xx();
public bbb()
{
System.out.println("in bbb Constructor");
System.loadLibrary("sss");
}
}
sss.c
void * Java_bbb_xx_stub(void *z,void *e)
{
bbb_xx();
return z;
}
long bbb_xx()
{
printf("in bbb .. xx - Hi\n");
return 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
aaa.java
class aaa
{ public static void main(String s[])
{ bbb a;
a = new bbb();
a.xx();
System.out.println("After xx ");
}
}
class bbb
{
int a , b;
public native void xx();
public bbb()
{
a=10;
b=20;
System.out.println("in bbb Constructor");
System.loadLibrary("sss");
}
}
sss.c
#include <StubPreamble.h>
struct zzz
{
long x,y;
};
struct yyy
{
struct zzz *o;
void * m;
};
stack_item * Java_bbb_xx_stub(stack_item *z,void * e)
{
printf("The sizeof stack_item..%d\n",sizeof(stack_item));
bbb_xx(z->p);
return z;
}
long bbb_xx(struct yyy * t)
{
printf("in bbb .. xx - Hi\n");
printf("Value of x %ld\n",t->o->x);
printf("Value of y %ld\n",t->o->y);
return 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
In the Options Tools Directory
D:\Java\Include
D:\Java\Include\Win32
aaa.java
class aaa
{ public static void main(String s[])
{ bbb a;
a = new bbb();
System.out.println("After a..."+a.a);
a.xx();
System.out.println("After a..."+a.a);
}
}
class bbb
{
int a , b;
public native int xx();
public bbb()
{
a=10;
b=20;
System.out.println("in bbb");
System.loadLibrary("sss");
}
}
sss.c
#include <StubPreamble.h>
struct zzz
{
long x,y;
};
struct yyy
{
struct zzz *o;
void *m;
};
stack_item * Java_bbb_xx_stub(stack_item *z,void *e)
{
bbb_xx(z->p);
return z+1;
}
long bbb_xx(struct yyy * t)
{
printf("in bbb .. xx - Hi\n");
printf("Value of x %ld\n",t->o->x);
printf("Value of y %ld\n",t->o->y);
t->o->x = 200;
return 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
aaa.java
class aaa
{ public static void main(String s[])
{ int i;
bbb a;
a = new bbb();
i=a.xx();
System.out.println("i = Return of xx =" + i);
}
}
class bbb
{
int a , b;
public native int xx();
public bbb()
{
a=10;
b=20;
System.out.println("in bbb");
System.loadLibrary("sss");
}
}
sss.c
#include <StubPreamble.h>
struct zzz
{
long x,y;
};
struct yyy
{
struct zzz *o;
void *m;
};
stack_item * Java_bbb_xx_stub(stack_item *z,void *e)
{
z->i=bbb_xx(z->p);
return z+1;
}
long bbb_xx(struct yyy * t)
{
printf("in bbb .. xx - Hi\n");
printf("Value of x %ld\n",t->o->x);
printf("Value of y %ld\n",t->o->y);
return 200;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
aaa.java
class aaa
{ public static void main(String s[])
{ int i;
bbb a;
a = new bbb();
a.xx(200);
System.out.println("After xx");
}
}
class bbb
{
int a , b;
public native int xx(int p);
public bbb()
{
a=10;
b=20;
System.out.println("in bbb");
System.loadLibrary("sss");
}
}
sss.c
#include <StubPreamble.h>
struct zzz
{
long x,y;
};
struct yyy
{
struct zzz *o;
void *m;
};
stack_item * Java_bbb_xx_stub(stack_item *z,void *e)
{
bbb_xx(z->p,z[1].i);
return z+1;
}
long bbb_xx(struct yyy * t,long u)
{
printf("in bbb .. xx - Hi\n");
printf("Value of u - %d\n",u);
return 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
aaa.java
class aaa
{ public static void main(String s[])
{
bbb a;
a = new bbb();
System.out.println("Value of a.."+a.a+"..b.."+a.b);
a.xx(200,3);
System.out.println("After xx");
System.out.println("Value of a.."+a.a+"..b.."+a.b);
}
}
class bbb
{
int a,b;
public native int xx(int p,int q);
public bbb()
{ a=10;
b = 20;
System.out.println("in bbb");
System.loadLibrary("sss");
}
}
sss.c
#include <StubPreamble.h>
struct zzz
{
long x,y;
};
struct yyy
{
struct zzz *o;
void *m;
};
stack_item * Java_bbb_xx_stub(stack_item *z,void *e)
{
bbb_xx(z->p,z[1].i,z[2].i);
return z;
}
long bbb_xx(struct yyy * t,long u,long v)
{
printf("in bbb .. xx - Hi\n");
printf("Value of u-%d..v-%d\n",u,v);
t->o->x=u;
t->o->y=v;
return 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
aaa.java
class aaa
{
public static void main(String s[])
{ byte t[];
bbb b;
int c=0;
b = new bbb("a.txt");
t = new byte[1];
b.xx();
System.out.println("After open");
while (b.yy(t,1) == 1)
c++;
System.out.println("No. of characters."+c);
}
}
class bbb {
String s;
int d;
public bbb(String p)
{
System.out.println("in constructor");
System.loadLibrary("sss");
s=p;
}
public native boolean xx();
public native int yy (byte b[], int l);
}
sss.c
#include <StubPreamble.h>
#include <fcntl.h>
struct zzz
{
struct Hjava_lang_String * p;
long f;
};
struct yyy
{
struct zzz * o;
void * m;
};
long bbb_xx(struct yyy * t)
{
int g;
char u[1000];
javaString2CString(t->o->p,u,1000);
g = open(u,O_RDONLY);
printf("After open\n");
t->o->f = g;
printf("File handle g=%d...\n",g);
return 1;
}
struct pp
{
char b[1];
};
struct qq
{
struct pp * o;
void *m;
} ;
long bbb_yy(struct yyy * t,struct qq * v, long c)
{
char *d = v->o->b;
int q = c;
q = read(t->o->f,d,q);
if(q == 0)
return (-1);
printf("No. of char q=%d...Character *d=%c\n",q,*d);
return (q);
}
stack_item * Java_bbb_xx_stub(stack_item * z, void *e)
{
bbb_xx(z->p);
return z + 1;
}
stack_item * Java_bbb_yy_stub(stack_item * z, void * e)
{
z->i=bbb_yy(z->p,((z[1].p)),((z[2].i)));
return z + 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
Java_bbb_yy_stub
OR
__declspec (dllexport) stack_item * Java_bbb_xx_stub(stack_item * z, void *e)
{
bbb_xx(z->p);
return z + 1;
}
__declspec (dllexport) stack_item * Java_bbb_yy_stub(stack_item * z, void * e)
{
z->i=bbb_yy(z->p,((z[1].p)),((z[2].i)));
return z + 1;
}
There is no need for exporting these functions in the .def file.
Project Files will be
sss.c
javai.lib
aaa.java
class aaa
{ public static void main(String s[])
{
bbb b;
b = new bbb();
b.xx();
}
}
class bbb
{
int a;
public native int xx();
public bbb()
{ a=10;
System.out.println("in bbb Constructor");
System.loadLibrary("sss");
}
public void ppp()
{
System.out.println("In ppp");
}
public void qqq()
{
System.out.println("In qqq");
}
}
sss.c
#include <StubPreamble.h>
struct mt
{
struct ClassClass *c;
void *md[1];
};
struct zzz
{
long x;
};
struct yyy
{
struct zzz *o;
struct mt *m;
};
stack_item * Java_bbb_xx_stub(stack_item *z,void *e)
{
bbb_xx(z->p);
return z;
}
long bbb_xx(struct yyy * t)
{
printf("in bbb .. xx - Hi\n");
printf (" Name... %s\n",t->m->c->name);
printf ("Super Name.....%s\n",t->m->c->super_name);
printf("Source Name ...%s\n",t->m->c->source_name);
printf ("Methods count ..%d\n",t->m->c->methods_count);
printf ("Fields count....%d\n",t->m->c->fields_count);
printf ("Access .....%d\n",t->m->c->access);
printf("Flags....%d\n",t->m->c->flags);
return 1;
}
sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
Output
in bbb Constructor
in bbb .. xx - Hi
Name...bbb
Super Name.....java/lang/Object
Source Name... aaa.java
Methods count ..4
Fields count ....1
Access .....0
Flags....18
aaa.java
class aaa
{ public static void main(String s[])
{
bbb a;
a = new bbb();
a.xx();
}
}
class bbb
{
int a;
int b;
public native int xx();
public bbb()
{ a=10;
b = 30;
System.out.println("in bbb");
System.loadLibrary("sss");
}
public void ppp()
{
System.out.println("In ppp");
}
public void qqq()
{
System.out.println("In qqq");
}
}
sss.c
#include sss.def
LIBRARY sss
EXPORTS
Java_bbb_xx_stub
.
Step 1:
Create the file aaa.java with the following codeclass aaa { public static void main(String s[]) { bbb a; System.out.println("Start"); a = new bbb(); System.out.println("Before xx"); a.xx(); System.out.println("After xx"); } } class bbb { public native void xx(); public bbb() { System.out.println("in bbb"); System.loadLibrary("sss"); } }Step 2:javac aaa.java
Output aaa.class bbb.classStep 3:javah aaa
Output Error: java.lang.Object not found:abortingStep 4:set CLASSPATH=d:\java\lib\classes.zip
Step 5:javah aaa
Output Error: aaa: no such classStep 6:set CLASSPATH=..;d:\java\lib\classes.zip
Step 7:javah aaa
Output aaa.h /* DO NOT EDIT THIS FILE - it is machine generated */ #include <native.h> /* Header for class aaa */ #ifndef _Included_aaa #define _Included_aaa typedef struct Classaaa { char PAD; /* ANSI C requires structures to have a least one member */ } Classaaa; HandleTo(aaa); #ifdef __cplusplus extern "C" { #endif #ifdef __cplusplus } #endif #endifStep 8:javah bbb
Output bbb.h /* DO NOT EDIT THIS FILE - it is machine generated */ #include <native.h> /* Header for class bbb */ #ifndef _Included_bbb #define _Included_bbb typedef struct Classbbb { char PAD; /* ANSI C requires structures to have a least one member */ } Classbbb; HandleTo(bbb); #ifdef __cplusplus extern "C" { #endif __declspec(dllexport) void bbb_xx(struct Hbbb *); #ifdef __cplusplus } #endif #endifStep 9:javah -stubs aaa
Output aaa.c /* DO NOT EDIT THIS FILE - it is machine generated */ #include <StubPreamble.h> /* Stubs for class aaa */Step 10:javah -stubs bbb
Output bbb.c /* DO NOT EDIT THIS FILE - it is machine generated */ #include <StubPreamble.h> /* Stubs for class bbb */ /* SYMBOL: "bbb/xx()V", Java_bbb_xx_stub */ __declspec(dllexport)stack_item*Java_bbb_xx_stub(stack_item *_P_,struct execenv *_EE_){ extern void bbb_xx(void *); (void) bbb_xx(_P_[0].p); return _P_; }Step 11:
Project Files should be aaa.c, bbb.c, sss.c Build a DLL Copy the DLL from the WinDebug directory to the current directory.Create a file called sss.c void bbb_xx(void *a) { printf ("In File sss - bbb-xx\n"); }Step 12:java aaa
Output In Start Before xx In File sss - bbb-xx After xx
Feel free to send us your comments , feedback , suggestions which are most welcomed. Tell us how we can improvise the tutorial.
Vijay Mukhi's Computer Institute
B-13, Everest Building, Tardeo, Bombay 400 034, India.
http://www.vijaymukhi.com
e-mail : vmukhi@giasbm01.vsnl.net.in