Java软件中级工程师笔试题复杂逻辑

Java软件中级工程师笔

试题复杂逻辑

Revised at 2 pm on December 25, 2020.

J2EE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; ethod(); } public void method() { } }

class Base { }

8、true or false？

package test;

public class Test { public static void main(String[] args) { String str1 = new String(\ String str2 = new String(\ StringBuffer sb1 = new StringBuffer(\ StringBuffer sb2 = new StringBuffer(\ } }

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 = \ String str2 = \ String str3 = new String(\ str3 = (); } }

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(\ BigInteger two = new BigInteger(\ BigInteger three = new BigInteger(\ BigInteger sum = new BigInteger(\ (one); (two); (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 set = new HashSet(); (\ (\ (\ (\ (\ for (Iterator it = (); ();) { } } }

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. null B. 0 C. Test

17、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; }