我试着从c++代码中调用一些java类。我试着这样做：
java

package com.make.sign;
public class MakeSign {

    public static void main(String[] args) {
        System.out.println("Hello, world!");
        if (1 <= args.length) {
          System.out.println(args[0]);
        }
      }

}

从c++：

const int kNumOptions = 3;
    JavaVMOption options[kNumOptions] = {
      { const_cast<char*>("-Xmx128m"), NULL },
      { const_cast<char*>("-verbose:gc"), NULL },
      { const_cast<char*>("-Djava.class.path=/home/my/JavaCTest"), NULL }
    };

    JavaVMInitArgs vm_args;
    vm_args.version = JNI_VERSION_1_6;
    vm_args.options = options;
    vm_args.nOptions = sizeof(options) / sizeof(JavaVMOption);
    assert(vm_args.nOptions == kNumOptions);

    JNIEnv* env = NULL;
    JavaVM* jvm = NULL;
    int res = JNI_CreateJavaVM(&jvm, reinterpret_cast<void**>(&env), &vm_args);
    if (res != JNI_OK) {
        std::cerr << "FAILED: JNI_CreateJavaVM " << res << std::endl;
        return ;
    }

    const char* kClassName = "com/make/sign/MakeSign";
    jclass cls = env->FindClass(kClassName);
    if (cls == NULL) {
        std::cerr << "FAILED: FindClass" << std::endl;
        return ;
    }

    const char* kMethodName = "main";
    jmethodID mid =
        env->GetStaticMethodID(cls, kMethodName, "([Ljava/lang/String;)V");
    if (mid == NULL) {
        std::cerr << "FAILED: GetStaticMethodID" << std::endl;
        return ;
    }

    const jsize kNumArgs = 1;
    jclass string_cls = env->FindClass("java/lang/String");
    jobject initial_element = NULL;
    jobjectArray method_args = env->NewObjectArray(kNumArgs, string_cls, initial_element);

    jstring method_args_0 = env->NewStringUTF("Hello, Java!");
    env->SetObjectArrayElement(method_args, 0, method_args_0);

    env->CallStaticVoidMethod(cls, mid, method_args);
    jvm->DestroyJavaVM();

我为makesign.java制作了javac，将makesign.class放到/home/my/javactest/。运行build c++程序并获取：failed:findclass
请帮助，为什么找不到类以及如何修复？谢谢！