Java软件中年级工程师笔试题复杂逻辑

J2E E部分1、运算符优先级问题，下面代码的结果是多少？（笔试）package test;public class Test {public static void main(String[] args) {int k = 0;int ret = ++k + k++ + ++k + k;// ret的值为多少}}2、运算符问题，下面代码分别输出什么？（笔试）package test;public class Test {public static void main(String[] args) {int i1 = 10, i2 = 10;}}3、下面代码的结果是什么？还是抛出异常？（笔试）package test;public class Test {public void myMethod(String str) {}public void myMethod(Object obj) {}public static void main(String[] args) {Test t = new Test();t.myMethod(null);}}4、假设今天是9月8日，下面代码输出什么？（笔试）package test;public class Test {public static void main(String[] args) {Date date = new Date();}}5、下面代码的输出结果是什么？package test;public class Test {public static void main(String[] args) {double val = 11.5;}}6、下面代码的结果是什么？package test;public class Test extends Base {public static void main(String[] args) {Base b = new Test();b.method();Test t = new Test();t.method();}@Overridepublic void method() {}}class Base {public void method() throws InterruptedException { }}7、以下代码的结果是什么？package test;public class Test extends Base {public static void main(String[] args) {new Test().method();}public void method() {}}class Base {}8、true or false？package test;public class Test {public static void main(String[] args) {String str1 = new String("abc");String str2 = new String("abc");StringBuffer sb1 = new StringBuffer("abc");StringBuffer sb2 = new StringBuffer("abc");}}9、输出的结果是什么？package test;public class Test {public static void main(String[] args) { }public int method1() {int x = 1;try {return x;} finally {++x;}}public int method2() {int x = 1;try {return x;} finally {return ++x;}}}这样呢？输出什么package test;public class Test {public static void main(String[] args) { }public static boolean method() {try {return true;} finally {return false;}}}10、方法m1和m2有区别吗？什么区别package test;public class Test {public static void main(String[] args) { }public synchronized void m1() {}public static synchronized void m2() {}}11、true or false？理由package test;public class Test {public static void main(String[] args) { Integer i1 = 127;Integer i2 = 127;i1 = 128;i2 = 128;}}12、true or false？理由package test;public class Test {public static void main(String[] args) { String str1 = "a";String str2 = "a";String str3 = new String("a");str3 = str3.intern();}}13、true or false？理由package test;public class Test {public static void main(String[] args) {}}14、以下代码输出是什么？package test;public class Test {public static void main(String[] args) { BigInteger one = new BigInteger("1");BigInteger two = new BigInteger("2");BigInteger three = new BigInteger("3");BigInteger sum = new BigInteger("0");sum.add(one);sum.add(two);sum.add(three);}}15、输出的结果是什么？12345？根据单词排序？还是？package test;public class Test {public static void main(String[] args) {Set<String> set = new HashSet<String>();set.add("one");set.add("two");set.add("three");set.add("four");set.add("five");for (Iterator<String> it = set.iterator(); it.hasNext();) {}}}16、以下代码输出的结果（笔试选择题）public class Test {public static void main(String[] args) {}}A. nullB. 0C. Test17、下面为一个单例的实现代码，请指出代码中有几个错误或不合理之处，并改正。

public class Test {public Test instance = null;public static Test getInstance() {if (instance == null) {instance = new Test();return instance;}}}18、编程输出一个目录下的所有目录及文件名称，目录之间用tab。

（笔试）19、从键盘读入10个整数，然后从大到小输出。

（笔试）20、如何迭代Map容器，手写个试试？答案：1、82、i1 + i2 = 1010 语法错误i1 * i2 = 100 i1 / i2 = 13、string4、5 195、1211.012.06、test test7、test.Test test.Base 8、true false9、12 false 10、A: synchronized static是某个类的范围，synchronized static cSync{}防止多个线程同时访问这个类中的synchronized static 方法。

它可以对类的所有对象实例起作用。

???B: synchronized 是某实例的范围，synchronized isSync(){}防止多个线程同时访问这个实例中的synchronized 方法。

11、true false 12、true false true13、false 14、015、two five one three four 16、B17、getInstance 无默认返回值instance?必须是static18、package test;public class Test {public static void main(String[] args) {new Test().read("D:/test", "");}public void read(String path, String tab) {File file = new File(path);File[] childFiles = file.listFiles();for (int i = 0; childFiles != null && i < childFiles.length; i++) { if (childFiles[i].isDirectory()) {read(childFiles[i].getPath(), tab + "\t");}}}}19、package test;public class Test {public static void main(String[] args) {Scanner in = new Scanner(System.in);// 注意这里的数组，不是int的Integer[] arr = new Integer[10];for (int i = 0; i < 10; i++) {arr[i] = in.nextInt();}Arrays.sort(arr, new Comparator<Integer>() {@Overridepublic int compare(Integer o1, Integer o2) {if (o1 > o2) return -1;if (o1 < o2) return 1;return 0;}});}}20、package test;public class Test {public static void main(String[] args) {Map<Class, String> m = new HashMap<Class, String>();Set<Entry<Class, String>> set = m.entrySet();Iterator<Entry<Class, String>> it = set.iterator();while (it.hasNext()) {Map.Entry<Class, String> entry = it.next();Class key = entry.getKey();String value = entry.getValue();}}}。