Exception in thread "main" java.lang.NullPointerExceptionException in thread "main" java.lang.NullPointerException at com.imooc.displaymenu.suxue.main(suxue.java:77)我引用方法就報錯? 最后一行就是錯誤的 public void showData(int[] N,int length) { for(int i=0;i<length;i++) { System.out.print(N[i]+" "); } System.out.println(); }77.dm.showData(a, a.length);