Cannot find any information on property 'allFileName' in a bean of type 'tom.jiafei.ListFile'

ListFile.java

package tom.jiafei;
import java.io.*;
import java.io.File;
import java.io.FilenameFilter;
class FileName implements FilenameFilter
{ String str=null;
FileName (String s)
{ str="."+s;
}
public boolean accept(File dir,String name)
{ return name.endsWith(str);
}
}
public class ListFile
{ String extendsName=null;
StringBuffer allFileName;
public void setExtendsName(String s)
{ extendsName=s;
}
public String getExtendsName()
{ return extendsName;
}
public StringBuffer getFileName()
{ File dir=new File("d:/2000");
FileName help=new FileName(extendsName);
String file_name[]=dir.list(help);
for(int i=0;i<file_name.length;i++)
{ allFileName.append(file_name[i]+" ");
}
return allFileName;
}