SCJP认证试题及答案

转载对题目和答案谨做参考

Q1

A method is ...

1) an implementation of an abstraction.

2) an attribute defining the property of a particular abstraction.

3) a category of objects.

4) an operation defining the behavior for a particular abstraction.

5) a blueprint for making operations.

Q2

An object is ...

1) what classes are instantiated from.

2) an instance of a class.

3) a blueprint for creating concrete realization of abstractions.

4) a reference to an attribute.

5) a variable.

Q3

Which line contains a constructor in this class definition?

public class Counter { // (1)

int current, step;

public Counter(int startValue, int stepValue) { // (2)

set(startValue);

setStepValue(stepValue);

}

public int get() { return current; } // (3)

public void set(int value) { current = value; } // (4)

public void setStepValue(int stepValue) { step = stepValue; } // (5) }

1) Code marked with (1) is a constructor

2) Code marked with (2) is a constructor

3) Code marked with (3) is a constructor

4) Code marked with (4) is a constructor

5) Code marked with (5) is a Constructor

Q4

Given that Thing is a class, how many objects and reference variables are created by the following code?

Thing item, stuff;

item = new Thing();

Thing entity = new Thing();

1) One object is created

2) Two objects are created

3) Three objects are created

4) One reference variable is created

5) Two reference variables are created

6) Three reference variables are created.

Q5

An instance member…

1) is also called a static member

2) is always a variable

3) is never a method

4) belongs to a single instance, not to the class as a whole

5) always represents an operation

Q6

How do objects pass messages in Java?

1) They pass messages by modifying each other's member variables

2) They pass messages by modifying the static member variables of each other's classes

3) They pass messages by calling each other's instance member methods

4) They pass messages by calling static member methods of each other's classes.

Q7

Given the following code, which statements are true?

class A {

int value1;

}

class B extends A {

int value2;

}

1) Class A extends class B.

2) Class B is the superclass of class A.

3) Class A inherits from class B.

4) Class B is a subclass of class A.

5) Objects of class A have a member variable named value2.

Q8

If this source code is contained in a file called SmallProg.java, what command should be used to compile it using the JDK?

public class SmallProg {

public static void main(String args[]) { System.out.println("Good luck!"); }

}

1) java SmallProg

2) avac SmallProg

3) java SmallProg.java

4) javac SmallProg.java

5) java SmallProg main

Q9

Given the following class, which statements can be inserted at position 1 without causing the code to fail compilation?

public class Q6db8 {

int a;

int b = 0;