Error: Pointer type needed instead of JNIEnv_

How to fix the error in
ret = (*env)->NewStringUTF(env, newstring);
C++ on solaris 10?

# CC -Kpic -G -o libfoo.so -I/usr/java/include -I/usr/java/include/
solaris foo.cpp -z text
"foo.cpp", line 26: Error: Pointer type needed instead of JNIEnv_.
1 Error(s) detected.

foo.cpp:
#include <algorithm>
#include <jni.h>
#include "JNIFoo.h"

JNIEXPORT jstring JNICALL Java_JNIFoo_nativeFoo (JNIEnv *env, jobject
obj)
{
int i;
int ds_ret;

char* newstring;

jstring ret = 0;

newstring = (char*)new char[30];

if(newstring == NULL)
{
return ret;
}

std::fill(newstring, newstring + 30, 0);

newstring = (char *) "foo: Test program of JNI.\n";

ret = (*env)->NewStringUTF(env, newstring);

delete [] newstring;

return ret;
}

JNIFoo.java:
public class JNIFoo {
    public native String nativeFoo();

    static {
        System.loadLibrary("foo");
    }

    public void print () {
    String str = nativeFoo();
    System.out.println(str);
    }

    public static void main(String[] args) {
    (new JNIFoo()).print();
    return;
    }
}

# javac JNIFoo.java
# javah -jni JNIFoo