Your program is absolutely fine. But you cannot pass a parameter in the command line Java Echo abcd, you are doing nothing with the args. The System.in method waits for a value to be entered at the instance when it is called.
Probably when u run the program thro editors, it may cause problem. But if you run using DOS-Prompt you will know clearly. Also get your character to be echoed you should convert it to type char e.g. System.out.print((char) i );