SCJP model question answer 5

41)
abstract class C1{
public void m1(){        //1
}}
abstract class C2{
 public void m2(){      //2
}}

compile time error at line1  

compile time error at line2

The code compiles fine

None of the above

Explanation:
since the class C2 is abstract it can contain abstract methods
Ans: 3


42)
interface I{
    void f1();              // 1
    public void f2();       // 2
    protected void f3();    // 3
    private void f4();      // 4
    abstract void f5();     // 5
}


line  1,2,3,4

line  3,4

line  3

line  2,3,4

line  3,4,5

Explanation:
all methods declared within an interface are implicitly public, a weaker access level can not be declared
Ans: 2

43)
abstract class vehicle{
    abstract public void speed();
}
class car extends vehicle{
public static void main (String args[])
    {
    vehicle ob1;       
    ob1=new car();   //1
}
}


compiletime error at line  1

forces the class car to be declared as abstract

Runtime Exception

None of the above

Explanation:
No Explanation Available
Ans: 2


44)
class command {
    public static void main (String[] a1)
    {
    System.out.println(a1.length());        
    System.out.println(a1[0]);              
    System.out.println(a1);                 
      }
}

compile time error at line1

compile time error at line2

compile time error at line3

Runtime exception

Explanation:
length is not a method. it's a variable
Ans: 1

45)
abstract class A {}   // 1
transient class B {}  // 2
private class C {}    // 3
static class D {}     // 4
Which of these declarations will not produce a compile-time error?


Ans: 1

Ans: 2

Ans: 3

Ans: 4

None of the above

Explanation:
The modifiers, private and static, can be applied to a nested class, but can not be applied to a class that is not nested transient is allowed only for variables.
Ans: 1

46)
class c1
{
    public void m1(Object o1)
    {
      System.out.println("object");
    }
public void m1(String o1)
{
        System.out.println("string");
}
public int m1(int c)
{
        return c;
}
public static void main(String a[])
{
       c1 ob1=new c1();
      ob1.m1("hai");
           
}
}

print object

prints string

compile time error

non of the above

Explanation:
No Explanation Available
Ans: 2


47)
public static double sin(double angle)
What are the units of the "angle" argument?

Degrees

Radians

Both

None of the above

Explanation:
No Explanation Available
Ans: 2


48)
class base
{
    base()
    {
     System.out.println("base");
    }
    base(int i1)
    {
    }
}
class Super extends base
{
 Super()
 {
     System.out.println("super");
      super(1);
   
  }
public static void main(String [] a)
{
      base b1=new  Super();
}
}

compile time error

prints base and super

prints super and base

none of the above

Explanation:
No Explanation Available
Ans: 1


49)
The Throwable class is the superclass of all exceptions in the Java language.


true

false

Ans: 1


50)
class C {
    private String get ( String str )
    {
              try
              {
                  throw new Exception ( ) ;
                  return str ;
              }
        catch ( Exception e )
              {
                  return null ;
              }
  }
  public static void main ( String peace [ ] ) {
          try
          {
                  System.out.println ( ( new C ( ) ).get ( " C " ) ) ;
          }
          catch ( Exception e )
          {
                  System.out.println( "Exception" ) ;
          }
  }
};


compile time error

prints Exception

the code compiles and runs fine

none of the above

Ans: 1