Start Quiz: OCJP 1z0-803 OCA1.7 Mock Exam Quiz by Pankaj

Question: public static void main(String[] args) { int []xx = null; for (int i : xx) { System.out.println(i); } }

Choices:

null

0

compilation fails

Java.lang.NullPointerException

Question: package ocjp; import java.util.ArrayList; interface Universe{ public void doStuff(); } class Star{ public void doStuff(){ System.out.println("twinkling star"); } } class Sun extends Star implements Universe{ public void doStuff(){ System.out.println("Shinning sun"); } } public class Test { public static void main(String[] args) { ArrayList<String> arrayList = new ArrayList<String>(); Sun obj2 = new Sun(); Star obj3 = obj2; ((Sun) obj3 ).doStuff(); ((Star)obj2 ).doStuff(); ((Universe)obj2).doStuff(); } }

Choices:

Shining Sun Shining Sun Shining Sun

Shining Sun Twinkling Star Shining Sun

Compilation fails

A ClassCastException is thrown at runtime

Question: public class Marklist { int num; public static void graceMarks(Marklist obj4) { obj4.num += 10; } public static void main(String[] args) { MarkList obj1 = new MarkList(); MarkList obj2 = obj1; MarkList obj1 = null; obj2.num = 60; graceMarks(obj2); } } How many objects are created in the memory runtime?

Choices:

1

2

3

4

Question: Which statement initializes a stringBuilder to a capacity of 128? A. StringBuilder sb = new String ("128"); B. StringBuilder sb = StringBuilder.setCapacity (128); C. StringBuilder sb = StringBuilder.getInstance (128); D. StringBuilder sb = new StringBuilder (128);

Choices:

StringBuilder sb = new String ("128");

StringBuilder sb = new StringBuilder (128);

StringBuilder sb = StringBuilder.getInstance (128);

StringBuilder sb = StringBuilder.setCapacity (128);

Question: abstract class X{ public abstract void methodX(); } interface Y{ public void methodY(); } Which two code fragments are valid?

Choices:

class Z extends X implements Y{ public void methodz(){} }

abstract class Z extends X implements Y{ public void methodz(){} }

class Z extends X implements Y{ public void methodX(){} }

abstract class Z extends X implements Y{ }

class Z extends X implements Y{ public void methodY(){} }

Question: public class Tester { static void test(int[] a) { int[] b = new int[2]; a = b; System.out.print(b.length); System.out.print(a.length); } public static void main(String[] args) { int[] a = new int[5]; test(a); System.out.print(a.length); } }

Choices:

225

200

222

255

Question: Long var = (long) 999; // Line 3 long x1 = var.longValue(); // Line 5 double x2 = var.longValue(); // Line 7 double x3 = (double) var.longValue(); // Line 9 Double x4 = Long.valueOf("999"); // Line 11 Number x5 = Integer.parseInt("999"); // Line 13 Long x6 = Integer.parseInt("999"); // Line 15 Which lines are not valid and produce compile time exception ?

Choices:

Line 3

Line 5

Line 7

Line 11

Line 15

Question: int[] a = new int[0]; a[0] = 5; System.out.println(a[0]);

Choices:

5

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at ocjp.Test.main(Test.java:7)

Compilation error, arrays cannot be initialized to zero size

Compilation error, it is a.length() not a.length

Question: String[][] arra = new String[3][]; arra[0] = new String[]{"rose", "lily"}; arra[1] = new String[]{"apple", "berry","cherry","grapes"}; arra[0] = new String[]{"beans", "carrot","potato"}; // insert code fragment here Which code fragment when inserted at line '// insert code fragment here', enables the code to successfully change arra elements to uppercase?

Choices:

String[][] arra = new String[3][]; arra[0] = new String[]{"rose", "lily"}; arra[1] = new String[]{"apple", "berry","cherry","grapes"}; arra[0] = new String[]{"beans", "carrot","potato"}; for (int i = 0; i < arra.length; i++) { for (int j=0; j < arra[i].length; j++) { arra[i][j] = arra[i][j].toUpperCase(); } }

for (int i = 0; i < 3; i++) { for (int j=0; j < 4; j++) { arra[i][j] = arra[i][j].toUpperCase(); } }

for (String a[]: arra) { for (String x:a) { x = x.toUpperCase(); } }

for (int i:arra.length) { for (String x:arra) { arra[i].toUpperCase(); } }

No one

Question: package ocjp; public class Test { public static void main(String[] args) { Test p = new Test(); try { p.doPrint(); p.doList(); } catch (Exception e) { System.out.println("Caught: "+e); } } public void doList() throws Exception{ throw new Error("error"); } public void doPrint()throws Exception{ throw new RuntimeException("RuntimeException"); } }

Choices:

Caught: java.lang.RuntimeException: RuntimeException

Caught: java.lang.RuntimeException: RuntimeException Caught: java.lang.Error: error

Caught: java.lang.RuntimeException: RuntimeException Exception in thread "main" java.lang.Error: error at ocjp.Program136.doList(Program136.java:15) at ocjp.Program136.main(Program136.java:9)

java.lang.RuntimeException: RuntimeException at ocjp.Program136.doPrint(Program136.java:19) at ocjp.Program136.main(Program136.java:8)

Question: public static void main(String[] args) { StringBuilder sb1 = new StringBuilder("Duke"); String str1= sb1.toString(); // insert code here System.out.println(str1 == str2); }

Choices:

String str2 = str1;

String str2 = new string (str1);

String str2 = sb1.toString();

String str2 = “Duke”;