OCPJP 6 Mock Exam – 20

1 . Which of the following are valid array construction?

1. int a[] = new int[];
2. int a[] = new int[10];
3. int a[10] = new int[];
4. int a[] = new a[10];

2 . Which of the following are valid array initialization?

1. new int[] = {1,2,3,4};
2. new int[10] = {1,2,3,4};
3. new int[] = 1,2,3,4;
4. new int[] = [1,2,3,4];

3 . What will be the output?

[code lang=”java”]
public class Test3{
public static void main(String args[]){
int arr[] = new int[10];
int i = 5;
arr[i++] = ++i+i++;
System.out.print(arr[5]+":"+arr[6]);
}
}
[/code]

Choose the one below:

1. 14:0
2. 0:14
3. 0:0
4. Compiler Error

4 . What will be the output?

[code lang=”java”]
public class Test4{
public static void main(String args[]){
int arr[] = new int[10];
int i = 5;
arr[i++] = i+++i++;
System.out.print(arr[5]+":"+arr[6]);
}
}
[/code]

Choose the one below:

1. 13:0
2. 14:0
3. 0:14
4. 0:13

5 . What will be the output?

[code lang=”java”]
public class Test5{
static Boolean bl[] = new Boolean[5];
public static void main(String args[]){
System.out.println(bl[0]);
}
}
[/code]

Choose the one below:

1. Null
2. False
3. True
4. Compiler Error

6 . Which of the following are valid array declarations?

1. String[][] a1 = String[20][20];
2. String[][] a2 = new String[20,20];
3. String[][] a3 = new String[20][20];
4. String a4[][] = new String[20][20];
5. String[] a5[] = new String[20][20];

7 . Which of the following code correctly creates an array of four initialized string objects?

1. String players[] = new String[4];
2. String players[] = {“”,””,””,””};
3. String players[];
4. players = new String[4];
5. None of the above

8 . What will be the output?

[code lang=”java”]
char[] c = new char[100];
[/code]

what is the value of c[50]?

Choose the one below:

1. 50
2. 49
3. ‘\u0000’
4. ‘\u0020’

9 . which of the following are valid arrays?

1. new float[10]={1,2};
2. new float[]={1,2};
3. new float={1,2};
4. None of the above

10 . What will be the output?

[code lang=”java”]
public class Test10{
public void method(int arr[]){
arr[0] = 10;
}
public static void main(String[] args){
int[] small = {1,2,3};
Test10 t= new Test10();
t.method(small);
System.out.println(small[0]);
}
}
[/code]

Choose the one below:

1. 0
2. 1
3. 0
4. None of the above

Answers

1 : 2 is correct. int a[] = new int[10];

2 : 1 is correct. new int[] = {1,2,3,4};

3 : 1 is correct. 14:0

4 : 1 is correct. 13:0

5 : 1 is correct. Null.

6 : 3,4 & 5 is correct.
3 . String[][] a3 = new String[20][20];
4 . String a4[][] = new String[20][20];
5 . String[] a5[] = new String[20][20];

7 : 2 is correct. String players[] = {“”,””,””,””};

8 : 3 is correct. ‘\u0000’

9 : 2 is correct. new float[]={1,2};

10 : 10.