scjp试题－scjpmockexam2.txt

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SCJP试题－SCJPMockExam2

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Question 1)
Which of the following are legal statements?

1) float f=1/3; 
2) int i=1/3; 
3) float f=1.01; 
4) double d=999d;

Answer to Question 1) 


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Question 2)
Which of the following are Java keywords?

1) NULL 
2) new 
3) instanceOf 
4) wend

Answer to Question 2) 


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Question 3)
Which of the following are valid statements?

1) System.out.println(1+1); 
2) int i=2+'2'; 
3) c
4) byte b=255;

Answer to Question 3) 


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Question 4)
Which of the following statements are true?

1) The garbage collection algorithm in Java is vendor implemented 
2) The size of primitives is platform dependent 
3) The default type for a numerical literal with decimal component is a float. 
4) You can modify the value in an Instance of the Integer class with the setValue method

Answer to Question 4) 


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Question 5)
Which of the following are true statements?

1) I/O in Java can only be performed using the Listener classes 
2) The RandomAccessFile class allows you to move directly to any point a file.
3) The creation of a named instance of the File class creates a matching file in the underlying operating system only when the close method is called. 
4) The characteristics of an instance of the File class such as the directory separator, depend on the current underlying operating system

Answer to Question 5) 


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Question 6).
Which of the following statements are true?

1) The instanceof operator can be used to determine if a reference is an instance of a class, but not an interface. 
2) The instanceof operator can be used to determine if a reference is an instance of a particular primitive wrapper class 
3) The instanceof operator will only determine if a reference is an instance of a class immediately above in the hierarchy but no further up the inheritance chain 
4) The instanceof operator can be used to determine if one reference is of the same class as another reference thus

Answer to Question 6) 


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Question 7)
Which of the following statements are true?

1) An interface can only contain method and not variables 
2) Interfaces cannot have constructors
3) A class may extend only one other class and implement only one interface 
4) Interfaces are the Java approach to addressing its lack of multiple inheritance, but require implementing classes to create the functionality of the Interfaces.

Answer to Question 7) 






Question 8)
Which of the following are valid statements

1) public class MyCalc extends Math 
2) Math.max(s); 
3) Math.round(9.99,1); 
4)Math.mod(4,10);

Answer to Question 8) 


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Question 9)
Which of the following are methods of the Runnable interface

1) run 
2) start 
3) yield 
4) stop

Answer to Question 9) 


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Question 10)
Which of the following statements are true?

1) A byte can represent between -128 to 127 
2) A byte can represent between -127 to 128 
3) A byte can represent between -256 to 256 
4) A char can represent between -2x2 pow 16 2 x2 pow 16 - 1

Answer to Question 10) 


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Question 11)
What will happen when you attempt to compile and run the following code 
class Base{ 
public void Base(){ 
System.out.println("Base"); 
} 
} 
public class In extends Base{ 
public static void main(String argv[]){ 
In i=new In(); 
} 
}

1) Compile time error Base is a keyword 
2) Compilation and no output at runtime 
3) Output of Base 
4) Runtime error Base has no valid constructor

Answer to Question 11) 


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Question 12)
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?

1) Compile time error, main is not correctly defined 
2) Run time error, main is not correctly defined 
3) Compilation and output of java 
4) Compilation and output of hello

Answer to Question 12) 


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Question 13) 

Which of the following statements are true?

1) If a class has any abstract methods it must be declared abstract itself. 
2) All methods in an abstract class must be declared as abstract 
3) When applied to a class, the final modifier means it cannot be sub-classed 
4) transient and volatile are Java modifiers

Answer to Question 13) 






Question 14)
Which of the following are valid methods? 


1) public static native void amethod(){} 
2) public static void ametic native void amethod(){} 
3) private protected void amethod(){} 
4) static native void amethod();

Answer to Question 14) 



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Question 15)
Which of the following statements are true?

1) Constructors cannot have a visibility modifier 
2) Constructors can be marked public and protected, but not private 
3) Constructors can only have a primitive return type 
4) Constructors are not inherited 


Answer to Question 15) 


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Question 16)
What will happen when you attempt to compile and run the following class?

class Base{
Base(int i){
System.out.println("Base");
}
}

class Severn extends Base{
public static void main(String argv[]){
Severn s = new Severn();
}
void Severn(){
System.out.println("Severn");
}
}

1) Compilation and output of the string "Severn" at runtime 
2) Compile time error 
3) Compilation and no output at runtime 
4) Compilation and output of the string "Base" 


Answer to Question 16) 


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Question 17)
Which of the following statements are true? 


1) static methods do not have access to the implicit variable called this 
2) A static method may be called without creating an instance of its class
3) A static method may not be overriden to be non-static 
4) A static method may not be overloaded

Answer to question 17) 


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Question 18)
Which of the following will compile without error? 


1)

char c='1'; 
System.out.println(c>>1);

2)

Integer i=Integer("1"); 
System.out.println(i>>1);

3)

int i=1; 
System.out.println(i<<<1);

4)

int i=1; 
System.out.println(i<<1);

Answer to Question 18) 


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Question 19)
Which of the following are true?

1) A component may have only one event listener attached at a time 
2) An event listener may be removed from a component 
3) The ActionListener interface has no corresponding Adapter class 
4) The processing of an event listener requires a try/catch block 


Answer to Question 19) 


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Question 20)
Which of the following are Java keywords?

1) sizeof 
2) main 
3) transient 
4) volatile

Answer to Question 20) 


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Question 21)
Which of the following statements are true?

1) The default constructor has a return type of void 
2) The default constructor takes a parameter of void 
3) The default constructor takes no parameters 
4) The default constructor is not created if the class has any constructors of its own. 


Answer to Question 21) 







Question 22)
Which of the following statements are true?

1) All of the variables in an interface are implicitly static 
2) All of the variables in an interface are implicitly final 
3) All of the methods in an interface are implicitly abstract 
4) A method in an interface can access class level variables 



Answer to Question 22) 



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Question 23)
Which of the following statements are true? 

1 ) The String class is implemented as a char array, elements are addressed using the stringname[] convention 
2) The + operator is overloaded for concatenation for the String class 
3) Strings are a primitive type in Java and the StringBuffer is used as the matching wrapper type 
4) The size of a string can be retrieved using the length property 


Answer to Question 23) 


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Question 24)
Which of the following statements are true?

1) A method in an interface must not have a body 
2) A class may extend one other class plus at most one interface 
3) A class may extends at most one other class plus implement many interfaces 
4) An class accesses an interface via the keyword uses 


Answer to Question 24) 


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Question 25)
Which of the following statements are true?

1) The following statement will produce a result of 1. System.out.println( -1 >>>2); 
2) Performing an unsigned left shift (<<<) on a negative number will always produce a negative number result 
3) The following statement will produce a result of zero, System.out.println(1 >>1); 
4) All the integer primitives in java are signed numbers

Answer to Question 25) 


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Question 26)
Which of the following statements are true?

1) The elements in a Java array can only be of primitive tray can only be of primitive types, not objects 
2) Arrays are initialized to default values wherever they are created 
3) An array may be dynamically resized using the setSize method 
4) You can find out the size of an array using the size method

Answer to Question 26) 


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Question 27)