(1) Yohanan the High Priest – who served in the High Priesthood after Shimon HaTzaddik/the Righteous ( see Mishnah Avot, Chapter 1, Mishnah 2 – who was one of the last of the Men of the Great Assembly).
(2) stopped the confession – Since Ezra fined the Levites in that he would not give to them the [First] Tithe, for when he went up [to the Land of Israel] from the Diaspora and the sons of Levi did not go up with him, he commanded that they should give the [First] Tithe to the Kohanim. So Yohanan the Kohen Gadol/High Priest abolished the Confession (see Deuteronomy 26:13-15), since he was unable to say [the words] (Deuteronomy 26:13): “[I have cleared out the consecrated portion from the house;] and I have given it to the Levite, [the stranger, the father, and the widow, just as You commanded me...].
(3) abolished the "wakers" – for the Levites would recite on each day on the platform/Dukhan (Psalms 44:24): “Rouse Yourself; why do You sleep, O LORD? [Awaken, do not reject us forever!].” He said (to them): Is there sleep before God? Therefore, he stood and abolished them.
(4) and the "strikers" – for they would wound the sacrificial calf between its horns in order that blood would fall into its eyes in order that he would not see and it would be easy to invert it and slaughter it. He stood and abolished it (i.e., this practice), for it appeared as a like having a blemish (making it unfit for the altar, for priestly service, etc.) and they established for them rings in the ground to draw the neck of the animal into it (by the use of a rope passing through it, drawing the animal’s head down- See Mishnah Middot, Chapter 3, Mishnah 5). [The word] "נוקפים" – striking – and an example of this: A person does not strike his finger from below (Talmud Hullin 7b).
(5) the hammer was heard in Jerusalem – those who engrave copper and iron would strike it with a hammer to do work that cannot be postponed without irretrievable loss which is permissible during Hol HaMoed [Intermediate Days] of the Festival [of Passover and Sukkot]. And he stood and abolished them because the thing grows too loud and there is a despising of the Festival.
(6) in his days one did not have to ask about demai – for he said to the people of his generation: just as the Great Priest’s Due (2% that went to a Kohen) has the punishment of the death penalty [for non-compliance with this regulation], so too the Terumat Ma’aser/the ten percent that the Levite gave to the Kohen and eatables forbidden pending the separation of sacred gifts carry the death penalty [for non-compliance]. And he ordained that they should take out from that which was doubtfully-tithed only the tithe of the tithe that the Levite owes to the Kohen and Second Tithe, and they should not remove from it First Tithe or the Poor Tithe (in years three and six), for they can say to the Levite or to the poor that he brought proof that it is eatables forbidden pending the separation of sacred gifts and they should take [them]. And from this ordinance onward, he whomever purchases produce from the market would not ask if they were properly prepared or not, but he can immediate separate from them the Priest’s Due, the tithe of the tithe that the Levite gives to the Kohen and Second Tithe and eat the remainder. For all who purchase produce from an am ha-aretz are considered doubtfully tithed.