Compilation fails.
An exception is thrown at runtime.
An instance of Forest is serialized.
A instance of Forest and an instance of Tree are both serialized.
第1题:
下列关于Test类的定义中,正确的是______。
A) class Test implements Runnabte{
public void run(){}
public void someMethod(){}
B) class Test implements Rnuuable{
public void run();
}
C) class Test implements Rnuuable{
public void someMethod();
}
D) class Test implements Rnuuable{
public void someMethod();{}
}
A.
B.
C.
D.
第2题:
下列哪个选项的java源文件代码片段是不正确的?
A.package testpackage; public class Test{ }
B.import java. io. *; package testpaekage; public class Test { }
C.import java.io.*; class Person { } public class Test { }
D.import java.io.*; import java. awt.*; public class Test{ }
第3题:
下列Java源程序结构中前三种语句的次序,正确的是
A.import, package, public class
B.import必为首,其他不限
C.public class, import, package
D.package, import, public class
第4题:
选择正确的语句填在下列程序的横线处,使程序正常运行。 package ch1; import java. io. *; import j ava. util. *; class C45 implements Seritizable ______Public Thread t = new Thread(new T45(), "t"); public intcnt = 0; public C45() { t. start ( ) class T45 implements Runnable public int[] a = new int[4]; public void run() { for(int i - 0; i < 4; i++) { a[i] - i +4; } } } public class ex45 { static String fileName = "ch1\\file45.txt"; public static void main(String[] args) throws Exception { C45 bj = new C45 (); FileOutputStream fos = new FileOutputStream(fileName); ObjectOutputStream os = new ObjectOutputStream(fos); oos. writeObject (obj); oos.clese (); fos.close (); System. out, println (obj . toString ( ) ); } }
A.transient
B.protected
C.package
D.final
第5题:
下列程序将类C15的对象写入文件filetxt,选择正确的语句填入下列程序的横线处。 package ch2; import java.util.*; import java.io.*; class C15______ { public iht a; public void setInt(int newa) { a = newa; } } public class Testl5 { pulibc static void main(String[] args) { C15 bj = new C15(); try { FileOutputStream fos =newFileOutputStream("ch2\\filel5.txt"); ObjectOutputStream os = ObjectOutputStream(fos); Obj.setInt(10); oos.writeObject(obj); oos.close (); fos.close(); } catch(IOException ioe) { ioe.printStackTrace(); } } }
A.implements Runnable
B.implements Sedalizable
C.extends Serializable
D.implements InputStream
第6题:
下列哪个方法可用于创建一个可运行的类? ( )
A.public class X implements Runable {public void run(){...,.,}}
B.public class X implements Thread {public void run(){......}}
C.public class X implements Thread {public int run(){……}}
D.public class X implements Runable {protected void run(){.....}}
第7题:
下列( )选项的java源文件代码片段是不正确的。
A.package testpackage; publicClass Test{}
B.import java.io.*; package testpackage: publicClass Test{}
C.import java.io.*; Class Person{} publicClass Test{}
D.import java.io.*; import java.awt.*; publicClass Test{}
第8题:
下面程序运行时输出的结果为
C:\Program Files is a directory.
将程序补充完整。
Import java.io.*;
public class DirTest {
public static void main(String[] args) {
File myDir=Flew File("C:/Program Files/");
System.out.println(myDir+(______.isDirectory()?"is":"is not")+"a directory.");
}
}
第9题:
下列代码的输出结果是( )。
class parent
{
void printme()
{
System.out.println("parent");
}
}
class child extends parent
{
void printme()
{
System. out.println("child");
}
void printall()
{
super, printme();
this.printme();
printme();
}
}
public class test
{
public static void main(String args[])
{
child myc=new child();
myc.printall();
}
}
A.import java.awt.*;
B.import java.applet.applet;
C.import java.io.*;
D.import java, awt.graphics;
第10题:
下列哪个选项的java源文件程序段是不正确的? ( )
A.package testpackage; public class Test{ }
B.import java.io.*; package testpackage; public class Test{ }
C.import java.i.*; class Person{} public class Test{ }
D.import java.io.*; import java.awt.*; public class Test { }