Java执行Linux指令为文件赋予权限无效

public class Demo {
    public static void main(String[] args) {
        String path = File.separator + "home" + File.separator + "admin" + File.separator + "zlib_decompress"; // zlib_decompress 路径
        String template = "chmod 777 %s";
        String command = String.format(template, path);
        String[] cmd = new String[] { "/bin/sh", "-c", "chmod 777 %s" };
        try {
            Runtime.getRuntime().exec(cmd); // chmod 777 /home/admin/zlib_decompress
        } catch (Exception e) {
            e.printStackTrace();