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单选题
Given this method in a class： public String toString（） { StringBuffer buffer = new StringBuffer（）； buffer.append（‟‟）； return buffer.toString（）； } Which is true？（）
A
This code is NOT thread-safe.
B
The programmer can replace StringBuffer with StringBuilder with no other changes.
C
This code will perform well and converting the code to use StringBuilder will not enhance the performance.
D
This code will perform poorly. For better performance， the code should be rewritten： return “<“+ this.name + “>”；
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更多 “单选题Given this method in a class： public String toString（） { StringBuffer buffer = new StringBuffer（）； buffer.append（‟‟）； return buffer.toString（）； } Which is true？（）A This code is NOT thread-safe.B The programmer can replace StringBuffer with StringBuilder with no other changes.C This code will perform well and converting the code to use StringBuilder will not enhance the performance.D This code will perform poorly. For better performance， the code should be rewritten： return ““+ this.name + “”；” 相关考题
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考题
public class foo { public static void main （Stringargs） { String s； system.out.printIn （“s=” + s）； } } What is the result？（）A、 The code compiles and “s=” is printed.B、 The code compiles and “s=null” is printed.C、 The code does not compile because string s is not initialized.D、 The code does not compile because string s cannot be referenced.E、 The code compiles， but a NullPointerException is thrown when toString is called.
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class A { public String toString （） { return “4”； } } class B extends A { 8. public String toString （） { return super.toString（） + “3”； } } public class Test { public static void main（Stringargs） { System.out.printIn（new B（））； } } What is the result？（） A、 Compilation succeeds and 4 is printed.B、 Compilation succeeds and 43 is printed.C、 An error on line 9 causes compilation to fail.D、 An error on line 14 causes compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.
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Which two allow the class Thing to be instantiated using new Thing（）？A、 public class Thing { }B、 public class Thing { public Thing（） {} }C、 public class Thing { public Thing（void） {} }D、 public class Thing { public Thing（String s） {} }E、 public class Thing { public void Thing（） {} public Thing（String s） {} }
考题
public String makinStrings（） { String s = “Fred”； s = s + “47”； s = s.substring（2， 5）； s = s.toUpperCase（）； return s.toString（）； } How many String objects will be created when this method is invoked？（） A、 1B、 2C、 3D、 4E、 5F、 6
考题
Given： 310-025 Leading the way in IT testing and certification tools， www.testking.com - 48 - public class foo { static String s； public static void main （Stringargs） { system.out.printIn （“s=” + s）； } } What is the result？（）A、 The code compiles and “s=” is printed.B、 The code compiles and “s=null” is printed.C、 The code does not compile because string s is not initialized.D、 The code does not compile because string s cannot be referenced.E、 The code compiles， but a NullPointerException is thrown when toString is called.
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public class foo { public static void main （String[]args） { String s； system.out.printIn （“s=” + s）； } } What is the result？（） A、 The code compiles and “s=” is printed.B、 The code compiles and “s=null” is printed.C、 The code does not compile because string s is not initialized.D、 The code does not compile because string s cannot be referenced.E、 The code compiles， but a NullPointerException is thrown when toString is called.
考题
Given this method in a class： public String toString（） { StringBuffer buffer = new StringBuffer（）； buffer.append（‟‟）； buffer.append（this.name）； buffer.append（‟‟）； return buffer.toString（）； } Which is true？（） A、 This code is NOT thread-safe.B、 The programmer can replace StringBuffer with StringBuilder with no other changes.C、 This code will perform well and converting the code to use StringBuilder will not enhance the performance.D、 This code will perform poorly. For better performance， the code should be rewritten： return ““+ this.name + “”；
考题
Given an EL function declared with：11. 12.spin 13.com.example.Spinner 14. 15.java.lang.String spinIt（） 16. 17. Which two are true？（）A、The function method must have the signature： public String spin（）.B、The method must be mapped to the logical name "spin" in the web.xml file.C、The function method must have the signature： public String spinIt（）.D、The function method must have the signature public static String spin（）.E、The function method must have the signature： public static String spinIt（）.F、The function class must be named Spinner， and must be in the package com.example.
考题
单选题1. class A { 2. public String toString （） { 3. return “4”； 4. } 5. } 6. class B extends A { 7. public String toString （） { 8. return super.toString（） + “3”； 9. } 10. } 11. public class Test { 12. public static void main（String[]args） { 13. System.out.printIn（new B（））； 14. } 15. } What is the result？（）A
Compilation succeeds and 4 is printed.B
Compilation succeeds and 43 is printed.C
An error on line 9 causes compilation to fail.D
An error on line 14 causes compilation to fail.E
Compilation succeeds but an exception is thrown at line 9.
考题
单选题public String makinStrings（） { String s = “Fred”； s = s + “47”； s = s.substring（2， 5）； s = s.toUpperCase（）； return s.toString（）； } How many String objects will be created when this method is invoked？（）A
1B
2C
3D
4E
5F
6
考题
单选题Given： 310-025 Leading the way in IT testing and certification tools， www.testking.com - 48 - public class foo { static String s； public static void main （Stringargs） { system.out.printIn （“s=” + s）； } } What is the result？（）A
The code compiles and “s=” is printed.B
The code compiles and “s=null” is printed.C
The code does not compile because string s is not initialized.D
The code does not compile because string s cannot be referenced.E
The code compiles， but a NullPointerException is thrown when toString is called.
考题
单选题1. class A { 3. public String to String（） { 4. return “4”； 5. } 6. } 7. class B extends A { 8. public String toString（） { 9. return super.toString（） + “3”； 10. } 11. } 12. public class Test { 13. public static void main （String[] args） { 14. System.out.printIn（new B（））； 15. } 16. } What is the result（ ）？A
Compilation succeeds and 4 is printed.B
Compilation …………… is printed.C
An error on line 9 cause compilation to fail.D
An error on line 14 cause compilation to fail.E
Compilation succeeds but an exception is thrown at line 9.
考题
单选题class A { public String toString （） { return “4”； } } class B extends A { 8. public String toString （） { return super.toString（） + “3”； } } public class Test { public static void main（Stringargs） { System.out.printIn（new B（））； } } What is the result？（）A
Compilation succeeds and 4 is printed.B
Compilation succeeds and 43 is printed.C
An error on line 9 causes compilation to fail.D
An error on line 14 causes compilation to fail.E
Compilation succeeds but an exception is thrown at line 9.
考题
多选题Which two allow the class Thing to be instantiated using new Thing（）？Apublic class Thing { }Bpublic class Thing { public Thing（） {} }Cpublic class Thing { public Thing（void） {} }Dpublic class Thing { public Thing（String s） {} }Epublic class Thing { public void Thing（） {} public Thing（String s） {} }
考题
填空题Given the following code, write a line of code that, when inserted at the indicated location, will make the overriding method in Extension invoke the overridden method in class Base on the current object. class Base { public void print（ ） { System.out.println("base"); } } class Extention extends Base { public void print（ ） { System.out.println("extension"); // insert line of implementation here } } public class Q294d { public static void main(String args[]) { Extention ext = new Extention（ ）; ext.print（ ）; } } Fill in a single line of implementation.（）
考题
单选题public class foo { public static void main （String[]args） { String s； system.out.printIn （“s=” + s）； } } What is the result？（）A
The code compiles and “s=” is printed.B
The code compiles and “s=null” is printed.C
The code does not compile because string s is not initialized.D
The code does not compile because string s cannot be referenced.E
The code compiles， but a NullPointerException is thrown when toString is called.
考题
单选题Given this method in a class： public String toString（） { StringBuffer buffer = new StringBuffer（）； buffer.append（‟‟）； return buffer.toString（）； } Which is true？（）A
This code is NOT thread-safe.B
The programmer can replace StringBuffer with StringBuilder with no other changes.C
This code will perform well and converting the code to use StringBuilder will not enhance the performance.D
This code will perform poorly. For better performance， the code should be rewritten： return ““+ this.name + “”；
考题
单选题public class Score implements Comparable { private int wins， losses； public Score（int w， int 1） { wins = w； losses = 1； } public int getWins（） { return wins； } public int getLosses（） { return losses； } public String toString（） { return “”； } // insert code here } Which method will complete this class？（）A
public int compareTo（Object o） {/*mode code here*/}B
public int compareTo（Score other） {/*more code here*/}C
public int compare（Score s1，Score s2）{/*more code here*/}D
public int compare（Object o1，Object o2）{/*more code here*/}
考题
单选题public class foo { public static void main （Stringargs） { String s； system.out.printIn （“s=” + s）； } } What is the result？（）A
The code compiles and “s=” is printed.B
The code compiles and “s=null” is printed.C
The code does not compile because string s is not initialized.D
The code does not compile because string s cannot be referenced.E
The code compiles， but a NullPointerException is thrown when toString is called.
考题
多选题Given an EL function declared with：11. 12.spin 13.com.example.Spinner 14. 15.java.lang.String spinIt（） 16. 17. Which two are true？（）AThe function method must have the signature： public String spin（）.BThe method must be mapped to the logical name spin in the web.xml file.CThe function method must have the signature： public String spinIt（）.DThe function method must have the signature public static String spin（）.EThe function method must have the signature： public static String spinIt（）.FThe function class must be named Spinner， and must be in the package com.example.
考题
单选题Given a class Repetition： 1. package utils； 2. 3. public class Repetition { 4. public static String twice（String s） { return s + s； } 5. } and given another class Demo： 1. // insert code here 2. 3. public class Demo { 4. public static void main（String[] args） { 5. System.out.println（twice（”pizza”））； 6. } 7. } Which code should be inserted at line 1 of Demo.java to compile and run Demo to print“pizzapizza”？（）A
import utils.*；B
static import utils.*；C
import utils.Repetition.*；D
static import utils.Repetition. *；E
import utils.Repetition.twice（）；F
import static utils.Repetition.twice；G
static import utils.Repetition.twice；
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