Java abstract interface與 interface的區別

我們常常遇到abstract class與 interface的區別，今天卻遇到了abstract interface，感覺interface不用abstract再修飾了啊。結論：事實也確實如此，編譯為.class文件后abstract interface成為了interface。

package com.abstractinterface;

public abstract interface DaemonUserSignal
{
  public abstract void signal();
}

package com.abstractinterface;

public interface DaemonUserSignal2
{
  public abstract void signal();
}

編程后結果比較：

D:\git\concurrent_crypto\target\classes\com\abstractinterface>javap DaemonUserSignal.class
Compiled from "DaemonUserSignal.java"
public interface com.abstractinterface.DaemonUserSignal {
  public abstract void signal();
}

D:\git\concurrent_crypto\target\classes\com\abstractinterface>javap DaemonUserSignal2.class
Compiled from "DaemonUserSignal2.java"
public interface com.abstractinterface.DaemonUserSignal2 {
  public abstract void signal();
}