Line 13
Line 14
Line 18
Line 20
第1题:
public class Test { public static void main (String args) { string foo = “blue”; string bar = foo; foo = “green”; System.out.printIn(bar); } } What is the result?()
第2题:
11. public class Test { 12. public void foo() { 13. assert false; 14. assert false; 15. } 16. public void bar(){ 17. while(true){ 18. assert false; 19. } 20. assert false; 21. } 22. } What causes compilation to fail?()
第3题:
public class Test{ public static void main( String[] argv ){ // insert statement here } } Which statement, inserted at line 3, produces the following output?() Exception in thread “main” java.lang.AssertionError: true at Test.main(Test.java:3)
第4题:
10. interface Foo {} 11. class Alpha implements Foo {} 12. class Beta extends Alpha {} 13. class Delta extends Beta { 14. public static void main( String[] args) { 15. Beta x = new Beta(); 16. // insert code here 17. } 18. } Which code, inserted at line 16, will cause a java.lang.ClassCastException?()
第5题:
Given: 10. class One { 11. void foo() { } 12. } 13. class Two extends One { 14. //insert method here 15. } Which three methods, inserted individually at line 14, will correctly complete class Two?()
第6题:
public void foo() { /* more code here */ }
private void foo() { /* more code here */ }
protected void foo() { /* more code here */ }
int foo() { /* more code here */ }
void foo() { /* more code here */ }
第7题:
Compilation will fail.
Compilation will succeed and the program will print “3”
Compilation will succeed but the program will throw a ClassCastException at line 6.
Compilation will succeed but the program will throw a ClassCastException at line 7.
第8题:
Compilation succeeds.
An error at line 2 causes compilation to fail.
An error at line 9 causes compilation to fail.
An error at line 10 causes compilation to fail.
An error at line 11 causes compilation to fail.
第9题:
i = 3
Compilation fails.
A ClassCastException is thrown at line 6.
A ClassCastException is thrown at line 7.
第10题:
java test
java -ea test
java test file1
java -ea test file1
java -ea test file1 file2
java -ea:test test file1
第11题:
StackOverflowError
NullPointerException
NumberFormatException
IllegalArgumentException
ExceptionlnlnitializerError
第12题:
第13题:
class One { public One foo() { return this; } } class Two extends One { public One foo() { return this; } } class Three extends Two { // insert method here } Which two methods, inserted individually, correctly complete the Three class?()
第14题:
public class Test { public static void main(String args[]) { class Foo { public int i = 3; } Object o = (Object)new Foo(); Foo foo = (Foo)o; System.out.println(“i = “ + foo.i); } } What is the result?()
第15题:
public class Test {} What is the prototype of the default constructor?()
第16题:
public class Foo { public int a; public Foo() { a = 3; } public void addFive() { a += 5; } } and: public class Bar extends Foo { public int a; public Bar() { a = 8; } public void addFive() { this.a +=5; } } invoked with: Foo foo = new Bar(); foo.addFive(); System.out.println(”Value: “+ foo.a); What is the result?()
第17题:
Value: 3
Value: 8
Value: 13
Compilation fails.
The code runs with no output.
An exception is thrown at runtime.
第18题:
Compilation fails.
The code compiles and the output is 2.
If lines 16, 17 and 18 were removed, compilation would fail.
If lines 24, 25 and 26 were removed, compilation would fail.
If lines 16, 17 and 18 were removed, the code would compile and the output would be 2.
If lines 24, 25 and 26 were removed, the code would compile and the output would be 1.
第19题:
Foo { public int bar() { return 1; } }
new Foo { public int bar() { return 1; } }
newFoo() { public int bar(){return 1; } }
new class Foo { public int bar() { return 1; } }
第20题:
Compilation fails.
Compilation succeeds with errors.
Compilation succeeds with warnings.
Compilation succeeds without warnings or errors.
第21题:
Alpha a = x;
Foo f= (Delta)x;
Foo f= (Alpha)x;
Beta b = (Beta)(Alpha)x;
第22题:
assert true;
assert false;
assert false : true;
assert false == true;
assert false: false;
第23题:
Line 13
Line 14
Line 18
Line 20
第24题:
Test()
Test(void)
public Test()
public Test(void)
public void Test()