You can configure the Eclipse Formatter configuration:
public Long getId() { return this.id; }
Is it possible to format small (single-line) definitions as single-line?
No: error 205973 is written to request such a formatting option.3 years later, it seems that this will not be realized.
Edit May 2001:
maleki mentions in response to an orbfish comment that at least you have control over areas of code that Eclipse may or may not format:
Java Development Guide> Links> Java Editor> Formatter Help Page
This is not a direct answer, but it can help:
As far as I know (and after a quick look), the default formatting does not provide this level of detail for customization. If this is important for business, you can find the Eclipse plugin (possibly commercial) that can be configured using these advanced rules.