下列语句的输出是: public class test{ public static void main(String []args){ A test1=new A(); A test2=new A(); A test3=new A(); test1.setId(); System.out.println("test1, id:"+test1.getId()+" diff:"+test1.getNextId()); test2.setId(); System.out.println("test1, id:"+test2.getId()+" diff:"+test2.getNextId()); test3.setId(); System.out.println("test1, id:"+test3.getId()+" diff:"+test3.getNextId()); test1.setId(); System.out.println("test1, id:"+test1.getId()+" diff:"+test1.getNextId()); } } class A{ public int getId(){ return id; } public void setId(){ id=base+diff; diff+=2; base=id; } public int getNextId(){ return diff; } private int id; private static int diff=1; private static int base=0; }