Only public and protected constructors are inherited from super class if the subclass is not in the same package.
Which constructor is valid in class BlaBla
BlaBla(BlaBla a)
private BlaBla()
public final BlaBla(int i)
public static BlaBla(char o)
Given the following code, which of these constructors can be added to class B without causing a compile time error? class A{ int i; public A(int x) { this.i = x; } } class B extends A{ int j; public B(int x, int y) { super(x); this.j = y; } }
B( ) { }
B(int y ) { j = y; }
B(int y ) { super(y*2 ); j = y; }
B(int y ) { i = y; j = y*2; }
B(int z ) { this(z, z); }
Consider the following array definitions: int[] array1, array2[]; int[][] array3; int[] array4[], array5[]; Which of the following are valid statements?
array2 = array3;
array2 = array4;
array1 = array2;
array4 = array1;
array5 = array3
What will be the result of trying to compile and execute of the following program? public class TestClass{ public static void main(String args[] ){ int i = 0 ; int[] iA = {10, 20} ; iA[i] = i = 30 ; System.out.println(""+ iA[ 0 ] + " " + iA[ 1 ] + " "+i) ; } }
It will throw ArrayIndexOutofBoundsException at Runtime.
Compile time Error.
It will prints 10 20 30
It will prints 30 20 30
It will prints 0 20 30
What will the following program print? class Test{ public static void main(String[] args){ int i = 4; int ia[][][] = new int[i][i = 3][i]; System.out.println( ia.length + ", " + ia[0].length+", "+ ia[0][0].length); } }
It will not compile.
3, 4, 3
3, 3, 3
4, 3, 4
4, 3, 3
Consider the following program... class ArrayTest{ public static void main(String[] args){ int ia[][] = { {1, 2}, null }; for (int i = 0; i < 2; i++) for (int j = 0; j < 2; j++) System.out.println(ia[i][j]); } } Which of the following statements are true?
It will throw an ArrayIndexOutOfBoundsException at Runtime.
It will throw a NullPointerException at Runtime.
It will compile and run without throwing any exceptions.
None of the above.
Consider the following class... class Test{ public static void main(String[ ] args){ int[] a = { 1, 2, 3, 4 }; int[] b = { 2, 3, 1, 0 }; System.out.println( a [ (a = b)[3] ] ); } } What will it print when compiled and run ?
It will throw ArrayIndexOutOfBoundsException when run.
It will print 1.
It will print 3.
It will print 4
It will print 0
Given the following program, which statements are true? // Filename: TestClass.java public class TestClass{ public static void main(String args[]){ A[] a, a1; B[] b; a = new A[10]; a1 = a; b = new B[20]; a = b; // 1 b = (B[]) a; // 2 b = (B[]) a1; // 3 } } class A { } class B extends A { }
Compile time error at line 3.
The program will throw a java.lang.ClassCastException at the line labelled 2 when run.
The program will throw a java.lang.ClassCastException at the line labelled 3 when run.
The program will compile and run if the (B[ ] ) cast in the line 2 and the whole line 3 is removed.
Which of these statements are true?
If a RuntimeException is not caught, the method will terminate and normal execution of the thread will resume.
An overriding method must declare that it throws the same exception classes as the method it overrides.
The main method of a program can declare that it throws checked exceptions.
A method declaring that it throws a certain exception class may throw instances of any subclass of that exception class.
finally blocks are executed if and only if an exception gets thrown while inside the corresponding try block.
Consider the following code... public class TestClass{ class MyException extends Exception {} public void myMethod() throws XXXX{ throw new MyException(); } }
Can we replace XXXX with MyException?
What will the following code print ? class Test{ public static void main(String[] args){ int k = 1; int[] a = { 1 }; k += (k = 4) * (k + 2); a[0] += (a[0] = 4) * (a[0] + 2); System.out.println( k + " , " + a[0]); } }
4 , 4
25 , 25
13 , 13
What will the following code print when compiled and run? class Base{ void methodA(){ System.out.println("base - MethodA"); } } class Sub extends Base{ public void methodA(){ System.out.println("sub - MethodA"); } public void methodB(){ System.out.println("sub - MethodB"); } public static void main(String args[]){ Base b=new Sub(); //1 b.methodA(); //2 b.methodB(); //3 } }
sub - MethodA and sub - MethodB
base - MethodA and sub - MethodB
Compile time error at //1
Compile time error at //2
Compile time error at //3
What will be printed? class A1 { static int i; } class A { public static void main(String[] args) { A1 a1 = null; System.out.println(a1.i); } }
10
This code will not compile.
NullpointerException will be thrown
0
What will be the output of: Short k = 9; Integer i = 9; System.out.println(k == i);
Please provide argumentation to your answer.
true
false
Compilation error
Exception in runtime
Other
Consider the following code: class A{ public XXX m1(int a){ return a*10/4-30; } } class A2 extends A{ public YYY m1(int a){ return a*10/4.0; } } What can be substituted for XXX and YYY so that it can compile without any problems?
int, int
int, double
double, double
double, int
Nothing, they are simply not compatible.
Consider the following code: class A{ A() { print(); } void print() { System.out.println("A"); } } class B extends A{ int i = Math.round(3.5f); public static void main(String[] args){ A a = new B(); a.print(); } void print() { System.out.println(i); } } What will be the output when class B is run ?
It will print A, 4.
It will print A, A
It will print 0, 4
It will print 4, 4
Consider : class A { public void perform_work(){} } class B extends A { public void perform_work(){} class C extends B { public void perform_work(){} } } How can you let perform_work() method of A to be called from an instance method in C?
( (A) this ).perform_work( );
super.perform_work( );
super.super.perform_work( );
this.super.perform_work( );
It is not possible.
Expression (s instanceof java.util.Date) will return false if 's' was declared as a variable of class java.lang.String .
