OCAJP7 part 3 - from book

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

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; } }

Consider the following array definitions: int[] array1, array2[]; int[][] array3; int[] array4[], array5[]; Which of the following are valid statements?

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) ; } }

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); } }

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?

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 ?

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 { }

Which of these statements are true?

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 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); } }

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]); } }

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 } }

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); } }

What will be the output of: Short k = 9; Integer i = 9; System.out.println(k == i); Please provide argumentation to your answer.

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?

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 ?

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?

Expression (s instanceof java.util.Date) will return false if 's' was declared as a variable of class java.lang.String .