回複：回複：extend J1, you will waiver again

I am a long reader in this forum and first answer to J waiver.Sorry, I type Chinese too slow.I think, one with J visa can read this answer.
If you completed J waiver and extend again your J program,not begin a new program, you do not require a new waiver. If your extension is to begin a new J program and get your new J visa or document with two-year home country resident requirement, you need a new J waiver.
Please remember, not anyone with J visa requires a J waiver. Someone of mainland china from Hongkong got his/her J-1 visa without two-year home country residence requriement does not do J waiver.