JavaCore Test 2

The number of characters in an object of a class String is given by

The method length() returns the number of characters.

The method size() returns the number of characters.

The member variable called length

The member variable called size

Which of these are core interfaces in the collection framework.

Array

Tree

LinkedList

Map

What will be the output of the program?

public class Foo 
 { 
 public static void main(String[] args) 
 {
 try 
 { 
 return; 
 } 
 finally 
 {
 System.out.println( "Finally" ); 
 } 
 } 
 }

Finally

An exception is thrown at runtime.

Compilation fails

The code runs with no output.

What would be the result?


 class test
 {
 public static void main(String[] args)
 {
 Date d = new Date(2011343412345L);
 DateFormat df = new DateFormat();
 System.out.println(df.format(d));
 }
 }

26 Sep, 2033

An exception is thrown at runtime.

2011343412345L

A compile time error.

Which statement is true regarding the creation of default constructor?

The default constructor initializes local variables.

The default constructor invokes the constructor of the superclass.

When class has only constructor with parameter, the compiler creates a Default constructor

The default constructor initializes the instance variables declared in the class.

Which statement about static inner class is true?

It must extend enclosing class.

It’s variables and methods must be static.

A static inner class does not require an instance of the enclosing class.

A static inner class cannot be a static member of outer class.

Which of the following are correct.

An import statement, if defined, must always be the first non-comment statement of the file.

Local variables cannot be declared as static.

private members are accessible to all classes in the same package.

An abstract class can be declared as final.

Which statement is true?


 public void test(int x) 
 { 
 int odd = 1; 
 if(odd) /* Line 4 */
 {
 System.out.println("odd"); 
 } 
 else 
 {
 System.out.println("even"); 
 } 
 }

Compilation fails.

"even" will always be output.

"odd" will always be output.

"odd" will be output for odd values of x, and "even" for even values.

Which method defined in Integer class can be used to convert an Integer object to primitive int type.

valueOf

intValue

getInt

getInteger

The number of characters in an object of a class String is given by

The member variable called size

The member variable called length

The method length() returns the number of characters

The method size() returns the number of characters

What would be the output?


 class Test
 {
 public static void main(String [] args) throws Exception
 {
 Vector data = new Vector();
 data.add("apple");
 data.add("mango");
 data.add("papaya");
 data.add("cherry");
 data.add("banana");
 data.add("apple");
 System.out.println(getData(data));
 }
 public static Vector getData(Vector v)
 {
 return new Vector(new HashSet(v));
 }
 }

[apple, banana, cherry, mango, papaya]

[banana, cherry, papaya, apple, mango]

[banana, cherry, papaya, apple, apple, mango]

Compile Error

Which code determines the int value data closer to, but not greater than, a double value b?

Int data = (int) Math.floor(b);

Int data = (int) Math.ceil(b);

Int data = (int) Math.min(b);

Int data = (int) Math.abs(b);

What is the result?


 public Class Test implements Runnable
 {
 public void run(Thread t)
 {
 System.out.println("Running...");
 }
 public static void main(String [] args)
 {
 new thread(new Test()).start();
 }
 }

Compile error.

Running... will be printed

Program exists without printing anything.

Exception is thrown.

What will be the output of the program?


 public class X 
 { 
 public static void main(String [] args) 
 {
 try 
 {
 badMethod(); 
 System.out.print("A"); 
 } 
 catch (RuntimeException ex) /* Line 10 */
 { 
 System.out.print("B"); 
 } 
 catch (Exception ex1) 
 { 
 System.out.print("C"); 
 } 
 finally 
 {
 System.out.print("D"); 
 } 
 System.out.print("E"); 
 } 
 public static void badMethod() 
 { 
 throw new RuntimeException(); 
 } 
 }

B

BCD

BD

BDE

Which cannot directly cause a thread to stop executing?

Calling the notify method on an object.

Calling wait method on an object.

Calling the start method on another Thread object.

Calling a yield method.

Which statement is true for the Class java.util.HashSet?

The elements in the collection are ordered.

The collection is guaranteed to be immutable

The elements in the collection are synchronized.

The elements in the collection are unique.

What will be the output of the program?


 public class X 
 { 
 public static void main(String [] args) 
 {
 try 
 {
 badMethod(); 
 System.out.print("A"); 
 } 
 catch (Exception ex) 
 {
 System.out.print("B"); 
 } 
 finally 
 {
 System.out.print("C"); 
 } 
 System.out.print("D"); 
 } 
 public static void badMethod() 
 {
 throw new Error(); /* Line 22 */
 } 
 }

C is printed before exiting with an error message.

ABCD

Compilation fails.

BC is printed before exiting with an error

What is valid returnType for getData?


 public Class returnData
 {
 getData(byte a, double z)
 {
 Rreturn (short)a/z * 10;
 }
 }

Double

Int

Byte

Short

What is the result?


 int index = 1;
 Boolean [] test = new Boolean[3];
 Boolean data = test[index];

data has the value of true

The code will not compile.

data has the value of false

data has the value of null

What will be the output of the program?


 class Exc0 extends Exception { } 
 class Exc1 extends Exc0 { } /* Line 2 */
 public class Test 
 { 
 public static void main(String args[]) 
 { 
 try 
 { 
 throw new Exc1(); /* Line 9 */
 } 
 catch (Exc0 e0) /* Line 11 */
 {
 System.out.println("Ex0 caught"); 
 } 
 catch (Exception e) 
 {
 System.out.println("exception caught"); 
 } 
 } 
 }

Compilation fails because of an error at line 2.

Compilation fails because of an error at line 9.

exception caught

Ex0 caught