java单选题库

a1,a2=new A();
4 protected protected 1 / 2 构造函数与类名相同 .java
编译Java Application 源程序文件将产生相应 的字节码文件，这些字节码文件的扩展名为( )。 You have a public class called myclass with the main method defined as follows public static void main(String parm[]){ System.out.println(parm[0]); } If you attempt to compile the class and run the program as follows java myclass hello What will happen? Which specifier essentially declares a variable a global variable? Which of the following statement prints smith\exam1\test.txt? Which of the following is the correct expression of character 4? Which of the following is not an advantage of using methods? Which of the following can be placed in the blank line in the following code? public class Test { private static int id;
下列说法正确的有( )
class中的constructor 不可省略
设已声明了一个类A的两个对象a1,a2，为了初始 化 a1和a2，下面语句正确的是 若JAVA程序中定义了3个类，编译后可生成（ ）个字节码文件。 哪个关键字修饰的变量和方法不能从其他类访问? 哪个关键字声明一个常量? 哪个表达式的结果为0.5? 不是构造函数特点的是（ ）
protected
0
5
x is 5 and y is 6
variables final MAX_LENGTH = 99.98; number += sum; true, 1, Null
Test.java程序代码如下： 1) public class Test{ 2) public static void main(String[] args){ 3) System.out.println(args[1]); 4) } 5) } 以上程序编译后用java Test 2 3 4 5运行的输出 结果是什么？ ( ) System.out.println("5" + 2);的输出结果应该 Suppose x is a char variable with a value 'b'. What is the Байду номын сангаасrintout of the statement System.out.println(++x)? Main()方法的返回类型是： Java的字符类型采用的是Unicode编码方案，每个 Unicode码占用（ ）个比特位 In the program segment below, which line prints? int x=3, y=5; if (x < y) System.out.println("X= "+x); System.out.println("Y= "+y); How many times will the print statement execute? for (x=0; x<=5; ++x) { System.out.println("X= "+x); --x;} Given: 1. public void go() { 2. String o = ""; 3. z: 4. for(int x = 0; x < 3; x++) { 5. for(int y = 0; y < 2; y++) { 6. if(x==1) break; 7. if(x==2 && y==1) break z; 8. o = o + x + y; 9. } 10. } 11. System.out.println(o); 12. } What is the result when the go() method is invoked?
Compile time error, main is not correctly defined
protected System.out.println("sm ith\exam1\test.txt"); 4 Using methods makes program run faster
this public static void m1() { _____.id = 45; } }
0
6
0
类具有封装性，所以类的 数据是不能被访问的
以下关于构造函数的描述错误的是 下述概念中不属于面向对象方法的是 下面的选项中，哪一项不属于“汽车类”的行为
构造函数的返回类型只能 是void型 对象、消息 启动
下列说法中，不正确的是(
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一个java源程序经过编译 后，得到的文件的扩展名 一定是.class
题干 一个字节包含 ________ 位 Which of the following statements is correct? java字节码文件的后缀是 Java ___________ can run from a Web browser Every statement in Java ends with ____ Computer can execute the code in ____________. ___________ translates high-level language program into machine language program 属于解释性程序是________ Which JDK command is correct to run a Java application in ByteCode.class? Suppose you define a Java class as follows: public class Test { } In order to compile this program, the source code should be stored in a file Suppose you define a Java class as follows: class Test { } In order to compile this program, the source code should be stored in a file main函数声明正确的是
一种全新的程序语言 java Test Java virtual machine VB Java language specification
Java language specification
Java程序的执行过程中用到一套JDK工具，其中 Java文档生成器 java.exe是指( ) Java语言具有许多优点和特点，哪个反映了Java 安全性 程序并行机制的特点？（ 下列关于Java语言的特点，描述错误的是（ ） Java是跨平台的编程语言 在 Java 中，由Java编译器自动导入，而无需在 程序中用import导入的包是（ ） 运行下段代码后，z的结果为?? int a = 1, z=0; do { ++z; } while(a < 0) 运行下段代码后，x的结果为? int x = 3; int y = 2; x *= y + 1; 有如下程序段: int total = 0; for ( int i = 0; i < 4; i++ ){ if ( i == 1) continue; if ( i == 2) break; total += i; } 则执行完该程序段后total的值为： 有关类的说法正确的是？ ( ) ava.applet
Which of the following can be placed in the blank line in the following code? public class Test { private int id; this public void m1() { _____.id = 45; } } Which access specifier allows class members to be accessed by any class in its own package? What is the value of b after execution? int x, b=0; for(x = 0; x <= 5; ++x){ if (x == 2) break; ++b; } What is the value of b after execution? int x, b=0; for(x = 0; x <= 5; ++x){ if (x == 2) continue; ++b; } What is the printout of the following code: double x = 5.5; int y = (int)x; System.out.println("x is " + x + " and y is " + y); To improve readability and maintainability, you should declare _________ instead of using literal values such as 3.14159. To declare a constant MAX_LENGTH inside a method with value 99.98, you write To add number to sum, you write The default value for data field of a boolean type, numeric type, object type is ___________, respectively