SCJP Overloading, Overriding, Runtime Type and Object Orientation free sample questions

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());         //1
System.out.println(a1[0]);               //2
System.out.println(a1);                  //3
        //2
}}

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

Explanation:
No Explanation Available

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

Explanation:
No Explanation Available

Ans: 1

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