SCJP程序员认证考试章节练习(2020.04.07)

单项选择题
1. public class ArrayTest { 2. public static void main （String[]args） { 3. float f1[]， f2[]； 4. f1 = new float [10]； 5. f2 = f1； 6. System.out.printIn （“f2[0]=” + f2[0]）； 7. } 8. } What is the result？（）
A. It prints f2[0] = 0.0
B. It prints f2[0] = NaN
C. An error at line 5 causes compile to fail.
D. An error at line 6 causes compile to fail.
E. An error at line 6 causes an exception at runtime.
单项选择题
What is the numerical range of a char？（）
A. 0 ... 32767
B. 0 ... 65535
C. –256 ... 255
D. –32768 ... 32767
E. Range is platform dependent.
多项选择题
Which two declarations prevent the overriding of a method？（）
A. Final void methoda（） {}
B. Void final methoda（） {}
C. Static void methoda（） {}
D. Static final void methoda（） {}
E. Final abstract void methoda（） {}
单项选择题
Which code， inserted at line 15， allows the class Sprite to compile？（）
A.Foo{public int bar（）{return 1；}}
B.new Foo{public int bar（）{return 1；}}
C.new Foo（）{public int bar（）{return 1；}}
D.new class Foo{public int bar（）{return 1；}}
单项选择题
int i = 1，j = 10； do { if（i>j） { break； }j--； } while （++i <5）； System.out.println（“i =” +i+” and j = “+j）；What is the result？（）
A. i = 6 and j = 5
B. i = 5 and j = 5
C. i = 6 and j = 4
D. i = 5 and j = 6
E. i = 6 and j = 6
单项选择题
Which statement is true about the class of an object that can reference the variable base？（）
A.It can be any class.
B.No class has access to base.
C.The class must belong to the geometry package.
D.The class must be a subclass of the class Hypotenuse.
单项选择题
Given the following code： public class Test { void printValue（int m）{ do { System.out.println（"The value is"+m）； } while（ --m > 10 ） } public static void main（String arg[]） { int i=10； Test t= new Test（）； t.printValue（i）； } } Which will be output？（）
A. The value is 8
B. The value is 9
C. The value is 10
D. The value is 11
多项选择题
1） class Person { 2） public void printValue（int i， int j） {/*…*/ } 3） public void printValue（int i）{/*...*/ } 4） } 5） public class Teacher extends Person { 6） public void printValue（） {/*...*/ } 7） public void printValue（int i） {/*...*/} 8） public static void main（String args[]）{ 9） Person t = new Teacher（）； 10） t.printValue（10）； 11） } 12） } Which method will the statement on line 10 call？（）
A. on line 2
B. on line 3
C. on line 6
D. on line 7
单项选择题
Which statement is true？（）
A. If only one thread is blocked in the wait method of an object， and another thread executes the modify on that same object， then the first thread immediately resumes execution.
B. If a thread is blocked in the wait method of an object， and another thread executes the notify method on the same object， it is still possible that the first thread might never resume execution.
C. If a thread is blocked in the wait method of an object， and another thread executes the notify method on the same object， then the first thread definitely resumes execution as a direct and sole consequence of the notify call.
D. If two threads are blocked in the wait method of one object， and another thread executes the notify method on the same object， then the first thread that executed the wait call first definitely resumes execution as a direct and sole consequence of the notify call.
单项选择题
static void test（） { try { String x=null； System.out.print（x.toString（） +“ “）； } finally { System.out.print（“finally “）； } } public static void main（String[] args） { try { test（）； } catch （Exception ex） { System.out.print（”exception “）； } } What is the result？（）
A. null
B. finally
C. null finally
D. Compilation fails.
E. finally exception