为什么heroku会给我这个“不兼容类型”错误？

Question

我试图在Heroku.com上部署我的不和谐机器人，但是我收到了一个奇怪的错误.下面是抛出错误的类的代码：

package main.Events.lavaplayer;

import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
import com.sedmelluq.discord.lavaplayer.track.playback.MutableAudioFrame;
import net.dv8tion.jda.api.audio.AudioSendHandler;
import org.jetbrains.annotations.Nullable;

import java.nio.ByteBuffer;

public class AudioPlayerSendHandler implements AudioSendHandler {
    private final AudioPlayer audioPlayer;
    private final ByteBuffer buffer;
    private final MutableAudioFrame frame;

    public AudioPlayerSendHandler(AudioPlayer audioPlayer) {
        this.audioPlayer = audioPlayer;
        this.buffer = ByteBuffer.allocate(1024);
        this.frame = new MutableAudioFrame();
        this.frame.setBuffer(buffer);
    }

    @Override
    public boolean canProvide() {
        return this.audioPlayer.provide(this.frame);
    }

    @Nullable
    @Override
    public ByteBuffer provide20MsAudio() {
        return this.buffer.flip();
    }

    @Override
    public boolean isOpus() {
        return true;
    }
}

这段代码在使用Intellij编译时不会给我带来任何问题，但是当我试图将它部署到Heroku时，它们会给出以下错误：

错误:不兼容类型: java.nio.Buffer不能转换为@org.jetbrains.annotations.Nullable java.nio.ByteBuffer返回this.buffer.flip();

Answer 1

flip返回一个Buffer而不是ByteBuffer，因此需要一个强制转换

public ByteBuffer provide20MsAudio() {
    return (ByteBuffer) buffer.flip();
}