ZipFile.addFolder will delete the whole folder that already exist in zipfile

[zeroonead]

Hello Sorry, English is not good. my zip4j version is 2.11.5, OS is windows 11, jdk 1.8,here is the code

ZipParameters zipParameters = new ZipParameters();  
zipParameters.setRootFolderNameInZip("lib");    
ZipFile zipFile = new ZipFile(apkPath);  
zipFile.addFolder(new File(myFolder), zipParameters);

the zipfile already exist the "lib" folder,some files like "lib/aa.txt" (the folder that i added did not have this files),but after zipFile.addFolder,the whole "lib" folder files was deleted, only the files that I added was lefted in zipfile.

what should I do to not delete the "lib" folder files that already exist in zipfile.