Add testing, add non-static field accessors.

.gitignore

@@ -0,0 +1 @@
+*.go-old

go.mod

@@ -0,0 +1,3 @@
+module git.wow.st/gmp/jni
+
+go 1.14

gojni.h

@@ -1,3 +1,7 @@
+#ifndef __ANDROID_API__
+__attribute__ ((visibility ("hidden"))) JavaVM *_jni_CreateJavaVM(const char **options, int nOptions);
+#endif /* __ANDROID_API__ */
+
 __attribute__ ((visibility ("hidden"))) jint _jni_GetEnv(JavaVM *vm, JNIEnv **env, jint version);
 __attribute__ ((visibility ("hidden"))) jint _jni_AttachCurrentThread(JavaVM *vm, JNIEnv **p_env, void *thr_args);
 __attribute__ ((visibility ("hidden"))) jint _jni_DetachCurrentThread(JavaVM *vm);
@@ -7,15 +11,20 @@ __attribute__ ((visibility ("hidden"))) void _jni_ExceptionClear(JNIEnv *env);
 __attribute__ ((visibility ("hidden"))) jclass _jni_GetObjectClass(JNIEnv *env, jobject obj);
 __attribute__ ((visibility ("hidden"))) jmethodID _jni_GetMethodID(JNIEnv *env, jclass clazz, const char *name, const char *sig);
 __attribute__ ((visibility ("hidden"))) jmethodID _jni_GetStaticMethodID(JNIEnv *env, jclass clazz, const char *name, const char *sig);
+__attribute__ ((visibility ("hidden"))) jfieldID _jni_GetFieldID(JNIEnv *env, jclass clazz, const char *name, const char *sig);
 __attribute__ ((visibility ("hidden"))) jfieldID _jni_GetStaticFieldID(JNIEnv *env, jclass clazz, const char *name, const char *sig);
 __attribute__ ((visibility ("hidden"))) jsize _jni_GetStringLength(JNIEnv *env, jstring str);
 __attribute__ ((visibility ("hidden"))) const jchar *_jni_GetStringChars(JNIEnv *env, jstring str);
 __attribute__ ((visibility ("hidden"))) jstring _jni_NewString(JNIEnv *env, const jchar *unicodeChars, jsize len);
 __attribute__ ((visibility ("hidden"))) jboolean _jni_IsSameObject(JNIEnv *env, jobject ref1, jobject ref2);
+__attribute__ ((visibility ("hidden"))) jboolean _jni_IsInstanceOf(JNIEnv *env, jobject obj, jclass cls);
 __attribute__ ((visibility ("hidden"))) jobject _jni_NewGlobalRef(JNIEnv *env, jobject obj);
 __attribute__ ((visibility ("hidden"))) void _jni_DeleteGlobalRef(JNIEnv *env, jobject obj);
+__attribute__ ((visibility ("hidden"))) jobject _jni_NewLocalRef(JNIEnv *env, jobject obj);
+__attribute__ ((visibility ("hidden"))) void _jni_DeleteLocalRef(JNIEnv *env, jobject obj);
 __attribute__ ((visibility ("hidden"))) jint _jni_CallStaticIntMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args);
 __attribute__ ((visibility ("hidden"))) jobject _jni_CallStaticObjectMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args);
+__attribute__ ((visibility ("hidden"))) jobject _jni_NewObjectA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args);
 __attribute__ ((visibility ("hidden"))) void _jni_CallStaticVoidMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args);
 __attribute__ ((visibility ("hidden"))) jobject _jni_CallObjectMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args);
 __attribute__ ((visibility ("hidden"))) jint _jni_CallIntMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args);
@@ -33,3 +42,12 @@ __attribute__ ((visibility ("hidden"))) jint _jni_GetStaticIntField(JNIEnv *env,
 __attribute__ ((visibility ("hidden"))) jlong _jni_GetStaticLongField(JNIEnv *env, jclass clazz, jfieldID fieldID);
 __attribute__ ((visibility ("hidden"))) jfloat _jni_GetStaticFloatField(JNIEnv *env, jclass clazz, jfieldID fieldID);
 __attribute__ ((visibility ("hidden"))) jdouble _jni_GetStaticDoubleField(JNIEnv *env, jclass clazz, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jobject _jni_GetObjectField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jboolean _jni_GetBooleanField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jbyte _jni_GetByteField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jchar _jni_GetCharField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jshort _jni_GetShortField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jint _jni_GetIntField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jlong _jni_GetLongField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jfloat _jni_GetFloatField(JNIEnv *env, jobject obj, jfieldID fieldID);
+__attribute__ ((visibility ("hidden"))) jdouble _jni_GetDoubleField(JNIEnv *env, jobject obj, jfieldID fieldID);

jni.c

@@ -1,5 +1,31 @@
+#include <stdlib.h>
 #include <jni.h>
 
+#ifndef __ANDROID_API__
+JavaVM *_jni_CreateJavaVM(char **optstrings, int nOptions) {
+	JavaVM *vm;
+	JNIEnv *p_env;
+	JavaVMInitArgs vm_args;
+	JavaVMOption *options = (JavaVMOption *)malloc(sizeof(JavaVMOption)*nOptions);
+	if (options != 0) {
+		int i;
+		for (i = 0; i < nOptions; i++) {
+			options[i].optionString = optstrings[i];
+		}
+		vm_args.nOptions = nOptions;
+		vm_args.options = options;
+	}
+	vm_args.version = JNI_VERSION_1_6;
+	vm_args.ignoreUnrecognized = 0;
+	jint res = JNI_CreateJavaVM(&vm, &p_env, &vm_args);
+	if (res < 0) {
+		printf("Can't create Java VM\n");
+		return 0;
+	}
+	return vm;
+}
+#endif /* __ANDROID_API__ */
+
 jint _jni_AttachCurrentThread(JavaVM *vm, JNIEnv **p_env, void *thr_args) {
 	return (*vm)->AttachCurrentThread(vm, p_env, thr_args);
 }
@@ -36,6 +62,10 @@ jmethodID _jni_GetStaticMethodID(JNIEnv *env, jclass clazz, const char *name, co
 	return (*env)->GetStaticMethodID(env, clazz, name, sig);
 }
 
+jfieldID _jni_GetFieldID(JNIEnv *env, jclass clazz, const char *name, const char *sig) {
+    return (*env)->GetFieldID(env, clazz, name, sig);
+}
+
 jfieldID _jni_GetStaticFieldID(JNIEnv *env, jclass clazz, const char *name, const char *sig) {
     return (*env)->GetStaticFieldID(env, clazz, name, sig);
 }
@@ -56,6 +86,10 @@ jboolean _jni_IsSameObject(JNIEnv *env, jobject ref1, jobject ref2) {
 	return (*env)->IsSameObject(env, ref1, ref2);
 }
 
+jboolean _jni_IsInstanceOf(JNIEnv *env, jobject obj, jclass cls) {
+	return (*env)->IsInstanceOf(env, obj, cls);
+}
+
 jobject _jni_NewGlobalRef(JNIEnv *env, jobject obj) {
 	return (*env)->NewGlobalRef(env, obj);
 }
@@ -64,6 +98,18 @@ void _jni_DeleteGlobalRef(JNIEnv *env, jobject obj) {
 	(*env)->DeleteGlobalRef(env, obj);
 }
 
+jobject _jni_NewLocalRef(JNIEnv *env, jobject obj) {
+	return (*env)->NewLocalRef(env, obj);
+}
+
+void _jni_DeleteLocalRef(JNIEnv *env, jobject obj) {
+	(*env)->DeleteLocalRef(env, obj);
+}
+
+jobject _jni_NewObjectA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args) {
+	return (*env)->NewObject(env, cls, method, args);
+}
+
 void _jni_CallStaticVoidMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args) {
 	(*env)->CallStaticVoidMethodA(env, cls, method, args);
 }
@@ -140,3 +186,39 @@ jdouble _jni_GetStaticDoubleField(JNIEnv *env, jclass clazz, jfieldID fieldID) {
     return (*env)->GetStaticDoubleField(env, clazz, fieldID);
 }
 
+jobject _jni_GetObjectField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetObjectField(env, obj, fieldID);
+}
+
+jboolean _jni_GetBooleanField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetBooleanField(env, obj, fieldID);
+}
+
+jbyte _jni_GetByteField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetByteField(env, obj, fieldID);
+}
+
+jchar _jni_GetCharField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetCharField(env, obj, fieldID);
+}
+
+jshort _jni_GetShortField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetShortField(env, obj, fieldID);
+}
+
+jint _jni_GetIntField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetIntField(env, obj, fieldID);
+}
+
+jlong _jni_GetLongField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetLongField(env, obj, fieldID);
+}
+
+jfloat _jni_GetFloatField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetFloatField(env, obj, fieldID);
+}
+
+jdouble _jni_GetDoubleField(JNIEnv *env, jobject obj, jfieldID fieldID) {
+    return (*env)->GetDoubleField(env, obj, fieldID);
+}
+

jni.go

@@ -4,8 +4,17 @@
 
 package jni
 
-// Package jni implements various helper functions for communicating with the Android JVM
+// Package jni implements various helper functions for communicating with the
-// though JNI.
+// Android JVM though JNI.
+
+/*
+#cgo CFLAGS: -Wall
+
+#include <stdlib.h>
+#include <jni.h>
+#include "gojni.h"
+*/
+import "C"
 
 import (
 	"errors"
@@ -16,16 +25,6 @@ import (
 	"unsafe"
 )
 
-/*
-#cgo CFLAGS: -Wall
-
-#include <jni.h>
-#include <stdlib.h>
-
-#include "gojni.h"
-*/
-import "C"
-
 type JVM struct {
 	jvm *C.JavaVM
 }
@@ -92,6 +91,25 @@ func CallStaticIntMethod(e Env, cls Class, method MethodID, args ...Value) (int,
 	return int(res), exception(e)
 }
 
+// FindClass finds a class with a given name, using the JVM's default
+// class loader.
+func FindClass(e Env, name string) Class {
+	mname := C.CString(name)
+	defer C.free(unsafe.Pointer(mname))
+	res := C._jni_FindClass(e.env, mname)
+	if err := exception(e); err != nil {
+		panic(err)
+	}
+	return Class(res)
+}
+
+// NewObject creates a new object given a class, initializer methodID, and
+// arguments (if any).
+func NewObject(e Env, cls Class, method MethodID, args ...Value) (Object, error) {
+	res := C._jni_NewObjectA(e.env, C.jclass(cls), C.jmethodID(method), varArgs(args))
+	return Object(res), exception(e)
+}
+
 func CallStaticVoidMethod(e Env, cls Class, method MethodID, args ...Value) error {
 	C._jni_CallStaticVoidMethodA(e.env, C.jclass(cls), C.jmethodID(method), varArgs(args))
 	return exception(e)
@@ -199,6 +217,22 @@ func GetObjectClass(e Env, obj Object) Class {
 	return Class(cls)
 }
 
+// IsInstanceOf returns true if the given object is an instance of the
+// given class.
+func IsInstanceOf(e Env, obj Object, cls Class) bool {
+	if obj == 0 {
+		panic("null object")
+	}
+	if cls == 0 {
+		panic("null class")
+	}
+	res := C._jni_IsInstanceOf(e.env, C.jobject(obj), C.jclass(cls))
+	if err := exception(e); err != nil {
+		panic(err)
+	}
+	return res == C.JNI_TRUE
+}
+
 // GetStaticMethodID returns the id for a static method. It panics if the method
 // wasn't found.
 func GetStaticMethodID(e Env, cls Class, name, signature string) MethodID {
@@ -213,6 +247,19 @@ func GetStaticMethodID(e Env, cls Class, name, signature string) MethodID {
 	return MethodID(m)
 }
 
+// GetFieldID returns the id for a field. It panics if the field wasn't found.
+func GetFieldID(e Env, cls Class, name, signature string) FieldID {
+	mname := C.CString(name)
+	defer C.free(unsafe.Pointer(mname))
+	msig := C.CString(signature)
+	defer C.free(unsafe.Pointer(msig))
+	m := C._jni_GetFieldID(e.env, C.jclass(cls), mname, msig)
+	if err := exception(e); err != nil {
+		panic(err)
+	}
+	return FieldID(m)
+}
+
 // GetStaticFieldID returns the id for a static field. It panics if the field
 // wasn't found.
 func GetStaticFieldID(e Env, cls Class, name, signature string) FieldID {
@@ -241,14 +288,26 @@ func GetMethodID(e Env, cls Class, name, signature string) MethodID {
 	return MethodID(m)
 }
 
+// NewGlobalRef creates a new global reference.
 func NewGlobalRef(e Env, obj Object) Object {
 	return Object(C._jni_NewGlobalRef(e.env, C.jobject(obj)))
 }
 
+// DeleteGlobalRef delets a global reference.
 func DeleteGlobalRef(e Env, obj Object) {
 	C._jni_DeleteGlobalRef(e.env, C.jobject(obj))
 }
 
+// NewLocalRef creates a new local reference to the given object.
+func NewLocalRef(e Env, obj Object) Object {
+	return Object(C._jni_NewLocalRef(e.env, C.jobject(obj)))
+}
+
+// DeleteLocalRef delets a local reference.
+func DeleteLocalRef(e Env, obj Object) {
+	C._jni_DeleteLocalRef(e.env, C.jobject(obj))
+}
+
 // JavaString converts the string to a JVM jstring.
 func JavaString(e Env, str string) String {
 	if str == "" {
@@ -364,3 +423,93 @@ func GetStaticDoubleField(env Env, clazz Class, fieldID FieldID) float64 {
 	}
 	return float64(value)
 }
+
+// GetObjectField looks up the value of a static field of type Object.
+// It panics if it is unable to find the field.
+func GetObjectField(env Env, obj Object, fieldID FieldID) Object {
+	value := C._jni_GetObjectField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return Object(value)
+}
+
+// GetBooleanField looks up the value of a static field of type boolean.
+// It panics if it is unable to find the field.
+func GetBooleanField(env Env, obj Object, fieldID FieldID) bool {
+	value := C._jni_GetBooleanField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return value != 0
+}
+
+// GetByteField looks up the value of a static field of type byte.
+// It panics if it is unable to find the field.
+func GetByteField(env Env, obj Object, fieldID FieldID) byte {
+	value := C._jni_GetByteField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return byte(value)
+}
+
+// GetCharField looks up the value of a static field of type char.
+// It panics if it is unable to find the field.
+func GetCharField(env Env, obj Object, fieldID FieldID) byte {
+	value := C._jni_GetCharField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return byte(value)
+}
+
+// GetShortField looks up the value of a static field of type short.
+// It panics if it is unable to find the field.
+func GetShortField(env Env, obj Object, fieldID FieldID) int16 {
+	value := C._jni_GetShortField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return int16(value)
+}
+
+// GetIntField looks up the value of a static field of type int.
+// It panics if it is unable to find the field.
+func GetIntField(env Env, obj Object, fieldID FieldID) int32 {
+	value := C._jni_GetIntField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return int32(value)
+}
+
+// GetLongField looks up the value of a static field of type long.
+// It panics if it is unable to find the field.
+func GetLongField(env Env, obj Object, fieldID FieldID) int64 {
+	value := C._jni_GetLongField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return int64(value)
+}
+
+// GetFloatField looks up the value of a static field of type float.
+// It panics if it is unable to find the field.
+func GetFloatField(env Env, obj Object, fieldID FieldID) float32 {
+	value := C._jni_GetFloatField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return float32(value)
+}
+
+// GetDoubleField looks up the value of a static field of type double.
+// It panics if it is unable to find the field.
+func GetDoubleField(env Env, obj Object, fieldID FieldID) float64 {
+	value := C._jni_GetDoubleField(env.env, C.jobject(obj), C.jfieldID(fieldID))
+	if err := exception(env); err != nil {
+		panic(err)
+	}
+	return float64(value)
+}

jni_darwin.go

@@ -0,0 +1,11 @@
+// +build darwin
+//go:generate ./find_jnih jni_darwin.go2
+//Generated by scripts/find_macos_jnih
+
+package jni
+
+/*
+#cgo CFLAGS: -I/Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home/include/darwin
+#cgo LDFLAGS: -ljvm
+*/
+import "C"

jni_notandroid.go

@@ -0,0 +1,37 @@
+// +build !android
+
+package jni
+
+/*
+#include <stdlib.h>
+#include <jni.h>
+#include "gojni.h"
+*/
+import "C"
+
+import (
+	"unsafe"
+)
+
+// CreateJavaVM creates a new Java VM with the options specified (if any).
+// This should not be called more than once as it can result in an error if
+// a JVM already exists for a given process.
+//
+// This is not implemented on Android and is therefore excluded on that
+// platform by build flags and C.
+func CreateJavaVM(opts ...string) JVM {
+	nOptions := len(opts)
+	optstrings := make([]*C.char, nOptions)
+	for i, _ := range optstrings {
+		optstrings[i] = C.CString(opts[i])
+		defer C.free(unsafe.Pointer(optstrings[i]))
+	}
+	var jvm *C.JavaVM
+	if nOptions > 0 {
+		jvm = C._jni_CreateJavaVM(&optstrings[0], C.int(nOptions))
+	} else {
+		jvm = C._jni_CreateJavaVM((**C.char)(nil), 0)
+	}
+	return JVM{ jvm: jvm }
+}
+

jni_test.go

@@ -0,0 +1,318 @@
+// +build darwin
+//go:generate javac test/AClass.java
+
+package jni
+
+import (
+	"sync"
+	"testing"
+)
+
+var (
+	vm JVM
+	vmOnce sync.Once
+)
+
+func TestCreateJVM(t *testing.T) {
+	// Do not try to create more than one JVM
+	vmOnce.Do(func() {
+		res := CreateJavaVM()
+		if res.jvm == nil {
+			t.Errorf("CreateJavaVM() returned nil")
+		} else {
+			vm = res
+		}
+	})
+}
+
+func TestFindClass(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		if cls == 0 {
+			t.Errorf("Class is nil")
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestGetMethodID(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestNewObject(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, err := NewObject(env, cls, mid)
+		if err != nil {
+			t.Errorf("NewObject raised exception")
+		}
+		if inst == 0 {
+			t.Errorf("NewObject returned nil")
+		}
+		inst = NewGlobalRef(env, inst)
+		if inst == 0 {
+			t.Errorf("NewGlobalRef returned nil")
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestIsSameObject(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, err := NewObject(env, cls, mid)
+		if !IsSameObject(env, inst, inst) {
+			t.Errorf("Object is not the same as itself")
+		}
+		inst2, err := NewObject(env, cls, mid)
+		if err != nil {
+			t.Errorf("Object is nil")
+		}
+		if IsSameObject(env, inst, inst2) {
+			t.Errorf("Different objects are the same")
+		}
+		inst2 = NewLocalRef(env, inst)
+		if !IsSameObject(env, inst, inst2) {
+			t.Errorf("New local ref is not the same as original object")
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestStaticIntMethod(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		mid = GetStaticMethodID(env, cls, "GetStaticInt", "()I")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		res, err := CallStaticIntMethod(env, cls, mid)
+		if err != nil {
+			t.Errorf("Method invocation failed")
+		}
+		if res != 100 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 100)
+		}
+		return err
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestIntMethod(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, err := NewObject(env, cls, mid)
+		mid = GetMethodID(env, cls, "GetInt", "()I")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		res, err := CallIntMethod(env, inst, mid)
+		if err != nil {
+			t.Errorf("Method invocation failed")
+		}
+		if res != 0 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 0)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestVoidMethod(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, err := NewObject(env, cls, mid)
+		mid = GetMethodID(env, cls, "IncInt", "()V")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		err = CallVoidMethod(env, inst, mid)
+		if err != nil {
+			t.Errorf("Method invocation failed")
+		}
+		mid = GetMethodID(env, cls, "GetInt", "()I")
+		res, err := CallIntMethod(env, inst, mid)
+		if err != nil {
+			t.Errorf("Method invocation falied")
+		}
+		if res != 1 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 1)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestVoidMethod2(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, err := NewObject(env, cls, mid)
+		mid = GetMethodID(env, cls, "SetInt", "(I)V")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		err = CallVoidMethod(env, inst, mid, 5)
+		if err != nil {
+			t.Errorf("Method invocation failed")
+		}
+		mid = GetMethodID(env, cls, "GetInt", "()I")
+		res, err := CallIntMethod(env, inst, mid)
+		if err != nil {
+			t.Errorf("Method invocation falied")
+		}
+		if res != 5 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 5)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestVoidMethod3(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, err := NewObject(env, cls, mid)
+		mid = GetMethodID(env, cls, "AddInts", "(II)V")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		err = CallVoidMethod(env, inst, mid, 9, 11)
+		if err != nil {
+			t.Errorf("Method invocation failed")
+		}
+		mid = GetMethodID(env, cls, "GetInt", "()I")
+		res, err := CallIntMethod(env, inst, mid)
+		if err != nil {
+			t.Errorf("Method invocation falied")
+		}
+		if res != 20 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 20)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestStaticVoidMethod(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetStaticMethodID(env, cls, "SetStaticInt", "(I)V")
+		if mid == nil {
+			t.Errorf("MethodID is nil")
+		}
+		err := CallStaticVoidMethod(env, cls, mid, 200)
+		if err != nil {
+			t.Errorf("Method invocation failed: %s", err)
+		}
+		mid = GetStaticMethodID(env, cls, "GetStaticInt", "()I")
+		res, err := CallStaticIntMethod(env, cls, mid)
+		if err != nil {
+			t.Errorf("Method invocation falied: %s", err)
+		}
+		if res != 200 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 200)
+		}
+		mid = GetStaticMethodID(env, cls, "SetStaticInt", "(I)V")
+		err = CallStaticVoidMethod(env, cls, mid, 100)
+		if err != nil {
+			t.Errorf("Method invocation failed: %s", err)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestGetObjectClass(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, _ := NewObject(env, cls, mid)
+		cls2 := GetObjectClass(env, inst)
+		if cls2 == 0 {
+			t.Errorf("GetObjectClass returned nil")
+		}
+		if !IsInstanceOf(env, inst, cls2) {
+			t.Errorf("IsInstanceOf failed")
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestField(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		mid := GetMethodID(env, cls, "<init>", "()V")
+		inst, _ := NewObject(env, cls, mid)
+		fid := GetFieldID(env, cls, "intval", "I")
+		if fid == nil {
+			t.Errorf("FieldID is nil")
+		}
+		res := GetIntField(env, inst, fid)
+		if res != 0 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 0)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}
+
+func TestStaticField(t *testing.T) {
+	err := Do(vm, func(env Env) error {
+		cls := FindClass(env, "test/AClass")
+		fid := GetStaticFieldID(env, cls, "staticintval", "I")
+		if fid == nil {
+			t.Errorf("FieldID is nil")
+		}
+		res := GetStaticIntField(env, cls, fid)
+		if res != 100 {
+			t.Errorf("Method returned %d, not expected value of %d.", res, 100)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Error: %s", err)
+	}
+}

scripts/find_macos_jnih

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+JAVA_HOME=`/usr/libexec/java_home`
+
+echo // +build darwin > jni_darwin.tmp
+echo //go:generate ./find_jnih jni_darwin.go2 >> jni_darwin.tmp
+echo //Generated by scripts/find_macos_jnih >> jni_darwin.tmp
+echo >> jni_darwin.tmp
+echo package jni >> jni_darwin.tmp
+echo >> jni_darwin.tmp
+echo /\* >> jni_darwin.tmp
+echo \#cgo CFLAGS: -I$JAVA_HOME/include -I$JAVA_HOME/include/darwin >> jni_darwin.tmp
+echo \#cgo LDFLAGS: -ljvm >> jni_darwin.tmp
+echo \*/ >> jni_darwin.tmp
+echo import \"C\" >> jni_darwin.tmp
+
+mv -f jni_darwin.go jni_darwin.go-old
+mv jni_darwin.tmp jni_darwin.go

test/AClass.java

@@ -0,0 +1,31 @@
+package test;
+
+public class AClass {
+	public static int staticintval = 100;
+
+	public int intval = 0;
+
+	public static int GetStaticInt() {
+		return staticintval;
+	}
+
+	public static void SetStaticInt(int val) {
+		staticintval = val;
+	}
+
+	public void IncInt() {
+		intval = intval + 1;
+	}
+
+	public int GetInt() {
+		return intval;
+	}
+
+	public void SetInt(int val) {
+		intval = val;
+	}
+
+	public void AddInts(int val1, int val2) {
+		intval = val1 + val2;
+	}
+}