public static void main(String[] args) { Power power = new Power(); power.on(); Workflow p1 = new Workflow("p1", power); Workflow p2 = new Workflow("p2", power); Workflow p3 = new Workflow("p3", power); Workflow p4 = new Workflow("p4", power); p2.waitFor(p1); p1.start(); p2.start(); p3.start(); p4.start(); try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } power.off(); try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } power.on(); try { Thread.sleep(500); } catch (InterruptedException e) { e.printStackTrace(); } p3.pause(1000); }