Process process = Runtime.getRuntime().exec("su");
DataOutputStream out = new DataOutputStream(process.getOutputStream());
out.writeBytes("mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /systemn");
out.writeBytes("cat /sdcard/myApp.apk > /system/app/myApp.apkn");
out.writeBytes("mount -o remount,ro -t yaffs2 /dev/block/mtdblock3 /systemn");
out.writeBytes("exitn");
out.flush();
process.waitFor();