Remove Whitespace from a Java Program
CJam, 25 bytes - 83 removed = -58

Since Java doesn't have multiline strings nor significant indentation, we can simply remove all leading spaces. Also, since there won't be any comments, and statements will not be split across lines (as per the OP's comments), I think I should be able to remove all newlines as well.

That makes for safe and short code with pretty decent savings for the test file:

q_,\N/{S\+e`1&gt;e~}%_oNos,-


Test it here.

For the test case it yields

class Condition {public static void main(String[] args) {boolean learning = true;if (learning == true) {System.out.println("Java programmer");}else {System.out.println("What are you doing here?");}}}
83