Closeable介面又繼承了另外的父介面AutoCloseable

其中close()方法是關閉流並且釋放與其相關的任何方法，如果流已被關閉，那麼呼叫此方法沒有效果。

InputStream和OutputStream類都實現了該介面。

原始碼：

package java.io;

import java.io.IOException;

/**
 * A {@code Closeable} is a source or destination of data that can be closed.
 * The close method is invoked to release resources that the object is
 * holding (such as open files).
 *
 * @since 1.5
 */
public interface Closeable extends AutoCloseable {

    /**
     * Closes this stream and releases any system resources associated
     * with it. If the stream is already closed then invoking this
     * method has no effect.
     *
     * <p> As noted in {@link AutoCloseable#close()}, cases where the
     * close may fail require careful attention. It is strongly advised
     * to relinquish the underlying resources and to internally
     * <em>mark</em> the {@code Closeable} as closed, prior to throwing
     * the {@code IOException}.
     *
     * @throws IOException if an I/O error occurs
     */
    public void close() throws IOException;
}