Can NetBeans remove trailing whitespace and change tabs to spaces on save?

For the first question, NetBeans 7.0+ has now a built-in solution. You can find it in:

On NetBeans 7:

Tools > Options > Editor > General > When saving files > Remove Trailing Whitespace: Never / Always / For Modified Lines Only

On NetBeans 8 / 9:

Tools > Options > Editor > On Save > Remove Trailing Whitespace From: None / All Lines / Modified Lines Only