What methods in Java are not allowed here?

Question

Java

Can't figure out which of the following method declarations are not valid and why? Ask to explain in detail, I would like to understand at least 1 point. I know Java, but I'm learning from trial and error, and in theory I can't explain it here. Thank you for your replies.

1. public final abstract int doAnything();
2. public abstract int doA(int j);
3. public private void notC(boolean flag);
4. final abstract boolean isEqual(float c, float d);

Answer 1

1. public final abstract int doAnything();
it makes sense to finalize a method that has no implementation
4. final abstract boolean isEqual(float c, float d);
there is also finalization and perhaps public is missing
3. public private void notC(boolean flag);
so the method is public or private
2. public abstract int doA(int j);
seems ok