Don't play with fire

src/android.rs

@@ -35,7 +35,7 @@ pub unsafe extern "C" fn Java_com_github_shadowsocks_bg_Tun2proxy_run(
             .with_filter(filter),
     );
     let proxy_url = get_java_string(&mut env, &proxy_url).unwrap();
-    let proxy = ArgProxy::try_from(proxy_url).unwrap();
+    let proxy = ArgProxy::try_from(proxy_url.as_str()).unwrap();
 
     let mut args = Args::default();
     args.proxy(proxy).tun_fd(Some(tun_fd)).dns(dns).verbosity(verbosity);
@@ -50,8 +50,6 @@ pub unsafe extern "C" fn Java_com_github_shadowsocks_bg_Tun2proxy_stop(_env: JNI
     crate::mobile_api::mobile_stop()
 }
 
-unsafe fn get_java_string<'a>(env: &'a mut JNIEnv, string: &'a JString) -> Result<&'a str, Error> {
-    let str_ptr = env.get_string(string)?.as_ptr();
-    let s: &str = std::ffi::CStr::from_ptr(str_ptr).to_str()?;
-    Ok(s)
+fn get_java_string(env: &mut JNIEnv, string: &JString) -> Result<String, Error> {
+    Ok(env.get_string(string)?.into())
 }