Federal judge drops corruption case against New York City Mayor Eric Adams

For Adams, yes.

But for the Department of Justice, no. They were trying to get the case dismissed solely in order to be able to threaten the mayor of New York. They (rightly) believe he's guilty, but (wrongly) believed that asking the judge to dismiss it would let them hold it over him forever.

Instead, the judge sidestepped that: he dismissed it "with prejudice". So Adams gets to walk free, but the administration doesn't get to use that as a threat. There was a serious "plague on both your houses" vibe from the judge.