java 笔试 面试 试题 计算机.docx

试题1已知变量a和obj的定义如下：Object a1 = “a”, “b”, “c” ;Object obj = a1;则下面语句运行时会抛出异常的是( )。A. Object a2 = (Object)obj;B. String str1 = (String)(Object)obj)1C. String a3 = (String)objD. String str2 = (String)a12 试题2已知类Foo的定义如下：public class Foo int value;Foo(int value) this.value = value;运行下面程序段：Foo a1 = new Foo(1), new Foo(2), new Foo(3) ;Foo a2 = new Fooa1.length;System.arraycopy(a1, 0, a2, 0, a1.length);System.out.println(a1 =