Java pdfbox 消息您没有关闭 PDF 文档

我有一个Java代码，它将pdf文件从目录复制到新的pdf文件，然后将其保存到另一个位置.但它抛出了:

Org.apache.pdfbox.cos.COSDocument Finalize 警告:警告:您未关闭PDF文档

但我确实关闭了PDF！

import org.apache.pdfbox.multipdf.Splitter;
import org.apache.pdfbox.pdmodel.PDDocument;

import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class Test {
    public static void main(String[] args) throws IOException{
        File srcFolder = new File(System.getProperty("user.dir") + "\\source");
        File[] srcFiles = srcFolder.listFiles();
        Arrays.sort(srcFiles);
        for (File srcFile : srcFiles) {
            PDDocument srcPDDocument = PDDocument.load(srcFile);
            PDDocument destPDDOcument = new PDDocument();
            
            Splitter splitting = new Splitter();
            
            List<PDDocument> pages = splitting.split(srcPDDocument);
            for (PDDocument page : pages) {
                destPDDOcument.addPage(page.getPage(0));
            }
            String dest = System.getProperty("user.dir") + "\\dest\\" + srcFile.getName();
            destPDDOcument.save(dest);
            destPDDOcument.close();
            srcPDDocument.close();
            System.out.println(srcFile.getName());
        }
    }
}