### Question:
SessionWindows { public static SessionWindows with(final long inactivityGapMs) { if (inactivityGapMs <= 0) { throw new IllegalArgumentException("Gap time (inactivityGapMs) cannot be zero or negative."); } return new SessionWindows(inactivityGapMs); } private  SessionWindows(final long gapMs); static SessionWindows with(final long inactivityGapMs); SessionWindows until(final long durationMs); long inactivityGap(); long maintainMs();  }### Answer:
@Test(expected = IllegalArgumentException.class) public void windowSizeMustNotBeNegative() { SessionWindows.with(-1); }
@Test(expected = IllegalArgumentException.class) public void windowSizeMustNotBeZero() { SessionWindows.with(0); }