// Create project instance
Project project = new Project(dataDir + "ConstraintStartNoEarlierThan.mpp");
        
// Set constraint Must Start On for task with Id 2
Task roof = project.getRootTask().getChildren().getById(2);
roof.set(Tsk.CONSTRAINT_TYPE, ConstraintType.MustFinishOn);

java.util.Calendar cal = java.util.Calendar.getInstance();
cal.set(2013, 6, 1, 18, 0, 0);
roof.set(Tsk.CONSTRAINT_DATE, cal.getTime());

// Save project as pdf
SaveOptions options = new PdfSaveOptions();
options.setStartDate(project.get(Prj.START_DATE));
options.setTimescale(Timescale.ThirdsOfMonths);
project.save(dataDir + "project_MustStartOn_out.pdf", options);