Sun Certified Java Programmer(SCJP 1.4)
Select all correct declarations, or declaration and initializations of an array?
A) String str[];
B) String str[5] = new String[5];
C) String str[] = new String[] {"string1", "string2", "string3", "string4", "string5"};
D) String str[] = {"string1","string2", "string3", "string4", "string5"};
2. Which of the following are the java keywords?
A) final
B) Abstract
C) Long
D) static
3. The synchronized is used in which of the following?
A) Class declarations.
B) Method declarations.
C) Block of code declarations
D) Variable declarations.
4. What will be printed when you execute the code?
class A {
A() {
System.out.println("Class A Constructor");
}
}
public class B extends A {
B() {
System.out.println("Class B Constructor");
}
public static void main(String args[]) {
B b = new B();
}
}
A) Class A Constructor followed by Class B Constructor
B) Class B Constructor followed by Class A Constructor
C) Compile time error
D) Run time error
5. Given the piece of code, select the correct to replace at the comment line?
class A {
A(int i) { }
}
public class B extends A {
B() {
// xxxxx
}
public static void main(String args[]) {
B b = new B();
}
}
A) super(100);
B) this(100);
C) super();
D) this();
6. Which of the statements are true?
A) Overridden methods have the same method name and signature
B) Overloaded methods have the same method name and signature
C) Overridden methods have the same method name and different signature
D) Overloaded methods have the same method name and different signature
7. What is the output when you execute the following code?
int i = 100;
switch (i) {
case 100:
System.out.println(i);
case 200:
System.out.println(i);
case 300:
System.out.println(i);
}
A) Nothing is printed
B) Compile time error
C) The values 100,100,100 printed
D) Only 100 is printed
8. How can you change the break statement below so that it breaks out of the inner and middle loops
and continues with the next iteration of the outer loop?
outer: for ( int x =0; x < 3; x++ ) {
middle: for ( int y=0; y < 3; y++ ) {
if ( y == 1) {
break;
}
}
}
A) continue middle
B) break middle:
C) break outer:
D) continue
9. What is the result of compiling the following code?
import java.io.*;
class MyExp {
void MyMethod() throws IOException, EOFException {
//............//
}
}
class MyExp1 extends MyExp {
void MyMethod() {
//..........//
}
}
public class MyExp2 extends MyExp1 {
void MyMethod() throws IOException {
//.........//
}
}
A) Compile time error
B) No compile time error
C) Run-Time error
D) MyMethod() cannot declare IOException in MyExp2 class
10. What is the result when you compile the and run the following code?
public class ThrowsDemo {
static void throwMethod() {
System.out.println("Inside throwMethod.");
throw new IllegalAccessException("demo");
}
public static void main(String args[]) {
try {
throwMethod();
} catch (IllegalAccessException e) {
System.out.println("Caught " + e);
}
}
}
A) Compilation error
B) Runtime error
C) Compile successfully, nothing is printed.
D) Inside throwMethod. followed by caught: java.lang.IllegalAccessExcption: demo
11. Which of the following statements about garbage collection are true?
A) The garbage collector runs in low memory situations
B) You can run the garbage collector when ever you want.
C) When it runs, it releases the memory allocated by an object, which is no more in use.
D) Garbage collector immediately runs when you set the references to null.
12. From the following code how many objects are eligible for garbage collection?
String string1 = "Test";
String string2 = "Today";
string1 = null;
string1 = string2;
A) 1
B) 2
C) 3
D) 0
13. Select all correct list of keywords or Java reserved words?
A) superclass
B) goto
C) open
D) integer
E) import, package
F) They are all java keywords
14. Select the correct anonymous inner class declaration ?
A) new Outer.new Inner
B) new Inner() { }
C) new Inner()
D) Outer.new Inner()
15. Which of the following statements are true?
A) An anonymous class cannot have any constructors
B) An anonymous class can only be created within the body of a method
C) An anonymous class can only access static fields of the enclosing class
D) An anonymous class instantiated and declared in the same place.
16. Which of the following class definitions are legal declaration of an abstract class?
A) class A { abstract void Method() {} }
B) abstract class A { abstract void Method() ; }
C) class A { abstract void Method() {System.out.println("Test");} }
D) class abstract A { abstract void Method() {} }
17. What is the result of compiling the following code?
public class Test {
public static void main ( String[] args) {
int value;
value = value + 1;
System.out.println(" The value is : " + value);
}
}
A) Compile and runs with no output
B) Compiles and runs printing out "The value is 1"
C) Does not compile
D) Compiles but generates run time error
18. What is the result of compiling the following code? When you run like given below?
java Test Hello How Are You
public class Test {
public static void main ( String[] args) {
for ( int i = 0; i < args.length; i++)
System.out.print(args[i]);
}
}
A) Compile and runs with no output
B) Compiles and runs printing out "HelloHowAreYou"
C) Does not compile
D) Compiles but generates run time error
19. Which are the following are java keywords ?
A) goto
B) synchronized
C) extends
D) implements
E) this
F) NULL
20. What is the output of the following code?
public class TestLocal {
public static void main(String args[]) {
String s[] = new String[6];
System.out.print(s[6]);
}
}
A) A null is printed
B) Compile time error
C) Exception is thrown
D) null followed by 0 is printed on the screen
21. Which of the following assignment statements is invalid?
A) long l = 698.65;
B) float f = 55.8;
C) double d = 0x45876;
D) All of the above
22. What is the numeric range for a Java int data type?
A) 0 to (2^32)
B) -(2^31) to (2^31)
C) -(2^31) to (2^31 - 1)
D) -(2^15) to (2^15 - 1)
23. How to represent number 7 as hexadecimal literal?
-----------
24. ------- is the range of the char data type?
25. Which of the following method returns the ID of an event?
A) int getID()
B) String getSource()
C) int returnID()
D) int eventID()
26. Which of the following are correct, if you compile the following code?
public class CloseWindow extends Frame implements WindowListener {
public CloseWindow() {
addWindowListener(this); // This is listener registration
setSize(300, 300);
setVisible(true);
}
public void windowClosing(WindowEvent e) {
System.exit(0);
}
public static void main(String args[]) {
CloseWindow CW = new CloseWindow();
}
}
A) Compile time error
B) Run time error
C) Code compiles but Frame does not listen to WindowEvents
D) Compile and runs successfully.
27. Select all correct answers from the following?
A) Java 1.0 event handling is compatible with event delegation model in Java 1.1
B) Java 1.0 and Java 1.1 event handling models are not compatible
C) Event listeners are the objects that implements listener interfaces.
D) You can add multiple listeners to any event source, then there is no guarantee that the listeners will be
notified in the order in which they were added.
28. Given the byte with a value of 01110111, which of the following statements will produce
00111011?
A) 0x77 << 1;
B) 0x77 >>> 1;
C) 0x77 >> 1;
D) None of the above
29. Which of the following will compile without error?
A) char c = 'a';
B) double d = 45.6;
C) int i = d;
D) int k = 8;
30. Which of the following returns true when replace with XXXXXXXXX?
public class TestType {
public static void main(String args[] ) {
Button b = new Button("BUTTON");
if( XXXXXXXXX) {
System.out.print("This is an instance of Button");
}
}
}
A) b instanceof Button
B) Button instanceof b
C) b == Button
D) Button == (Object) b
31. The statement X %= 5, can best described as?
A) A equals a divided by 5;
B) A equals A in 5 digit percentage form
C) A equals A modulus 5.
D) None of the above
32. What will happen when you attempt to compile and run the following code?
public class MyClass {
public static void main(String args[]) {
String s1 = new String("Test One");
String s2 = new String("Test One");
if ( s1== s2 ) {
System.out.println("Both are equal");
}
Boolean b = new Boolean(true);
Boolean b1 = new Boolean(false);
if ( b.equals(b1) ) {
System.out.println("These wrappers are equal");
}
}
}
A) Compile time error
B) Runtime error.
C) No output
D) These wrappers are equal
33. What is the result when you try to compile and run the following code?
public class TestBit {
public static void main(String args[]) {
String s = "HelloWorld";
if ((s != null) && (s.length() > 6))
System.out.println("The value of s is " + s );
}
}
A) Compile time error
B) Runtime error
C) No output is printed
D) The value of s is HelloWorld will be printed on the screen
34. Given the following declaration which of the following statements equals to true
boolean b1 = true;
boolean b2 = false;
A) b1 == b2;
B) b1 || b2;
C) b1 |& b2;
D) b1 && b2;
35. What is the result of the following code?
public class MyTest {
int x = 30;
public static void main(String args[]) {
int x = 20;
MyTest ta = new MyTest();
ta.Method(x);
System.out.println("The x value is " + x);
}
void Method(int y){
int x = y * y;
}
}
A) The x value is 20.
B) The x value is 30.
C) The x value is 400.
D) The x value is 600.
36. How can you implement encapsulation.
A) By making methods private and variable private
B) By making methods are public and variables as private
C) Make all variable are public and access them using methods
D) Making all methods and variables as protected.
37. Given the following class definition, which of the following methods could be legally placed after
the comment ?
public class Test{
public void amethod(int i, String s){}
//Here
}
A) public void amethod(String s, int i){}
B) public int amethod(int i, String s){}
C) public void amethod(int i, String mystring){}
D) public void Amethod(int i, String s) {}
38. Given the following class definition which of the following can be legally placed after the
comment line?
class Base{
public Base(int i){}
}
public class Derived extends Base{
public static void main(String arg[]){
Derived d = new Derived(10);
}
Derived(int i){
super(i);
}
Derived(String s, int i){
this(i);
//Here
}
}
A) Derived d = new Derived();
B) super();
C) this("Hello",10);
D) Base b = new Base(10);
39. Which of the following statements are true?
A) An inner class cannot be defined as private.
B) Static methods can be overridden by static methods only.
C) Static variables can be called using class name.
D) Non static variables can be called using class name.
40. What does the following code do?
public class RThread implements Runnable {
public void run (String s ) {
System.out.println ("Executing Runnable Interface Thread");
}
public static void main ( String args []) {
RThread rt = new RThread ( );
Thread t = new Thread (rt);
t.start ( );
}
}
A) The compiler error
B) The runtime error
C) Compiles and prints "Executing Runnable Interface Thread" on the screen
D) Compiles and does not print any thing on the screen
41. Which statements are true?
A) Threads start() method makes it eligible to run
B) Thread dies after the run() returns
C) A dead Thread can be started again.
D) A stop() method kills the currently running Thread
42. Which of the following are true?
A) A menu item generates an ActionEvent
B) A menu item generates ItemEvent
C) A menu item generates KeyEvent
D) A menu item generates TextEvent
43. Default Layout Managers are concerned ?
A) Frame's default layout manager is BorderLayout
B) Applet's is FlowLayout
C) Panel's is FlowLayout
D) A Dialog is a pop up window and uses BorderLayout as default.
44. Which statements are true about GridBagLayout ?
A) Weight x and weight y should be 0.0 and 1.0
B) If fill is both, anchor does not make sense.
C) It divides its territory in to an array of cells.
D) While constructing GridBagLayout, you won't tell how many rows and columns the underlying grid has.
45. Which of the following are true?
A) gridwidth, gridheight, specifies how many columns and rows to span.
B) gridx, gridy has GridBagConstraints.RELATIVE which adds left to right and top to bottom, still you can specify
gridwidth and gridheight except for last component, which you have to set GridBagConstraints.REMAINDER.
46. Which of the following statements are true about the fragment below?
import java.lang.Math;
public class Test {
public static void main(String args[]) {
Math m = new Math();
System.out.println(m.abs(2.6);
}
}
A) Compiler fails at line 1
B) Compiler fails at line 2
C) Compiler fails at the time of Math class instantiation
D) Compiler succeeds.
47. What will be the output of the following line?
public class TestFC {
public static void main(String args[]) {
System.out.println(Math.floor(145.1));
System.out.println(Math.ceil(-145.4));
}
}
A) 145.0 followed by -145.0
B) 150.0 followed by -150.0
C) 145.1 followed by -145.4
48. Which of the following prints "Equal"
A) int a = 10; float f = 10;
if ( a = = f) { System.out.println("Equal");}
B) Integer i = new Integer(10);
Double d = new Double(10);
if ( i = =d) { System.out.println("Equal");}
C) Integer a = new Integer(10);
int b = 10;
if ( a = = b) { System.out.println("Equal");}
D) String a = new String("10");
String b = new String("10");
if ( a = = b) { System.out.println("Equal");}
49. Which of the following implement clear notion of one item follows another (order)?
A) List
B) Set
C) Map
D) Iterator
50. Collection interface iterator method returns Iterator(like Enumerator), through you can traverse
a collection from start to finish and safely remove elements.
A) true
B) false
51. Which of the following places no constraints on the type of elements, order of elements, or
repetition of elements with in the collection.?
A) List
B) Collection
C) Map
D) Set
52. Which of the following gives Stack and Queue functionality.?
A) Map
B) Collection
C) List
D) Set
53. If you run the following code on a PC from the directory c:\source:
import java.io.*;
class Path {
public static void main(String[] args) throws Exception {
File file = new File("Ran.test");
System.out.println(file.getAbsolutePath());
}
}
What do you expect the output to be? Select the one right answer.
A) Ran.test
B) source\Ran.test
C) c:\source\Ran.test
D) c:\source
E) null
54. Which of the following will compile without error?
A) File f = new File("/","autoexec.bat");
B) DataInputStream d = new DataInputStream(System.in);
C) OutputStreamWriter o = new OutputStreamWriter(System.out);
D) RandomAccessFile r = new RandomAccessFile("OutFile");
55. You have an 8-bit file using the character set defined by ISO 8859-8. You are writing an
application to display this file in a TextArea. The local encoding is already set to 8859-8. How can
you write a chunk of code to read the first line from this file?
You have three variables accessible to you:
myfile is the name of the file you want to read
stream is an InputStream object associated with this file
s is a String object
Select all valid answers.
A)
InputStreamReader reader = new InputStreamReader(stream, "8859-8");
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
B)
InputStreamReader reader = new InputStreamReader(stream);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
C)
InputStreamReader reader = new InputStreamReader(myfile, "8859-8");
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
D)
InputStreamReader reader = new InputStreamReader(myfile);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
E)
FileReader reader = new FileReader(myfile);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
56. Which of the following used to read and write to network sockets, which are super classes of
Low level streams?
A) InputStream
B) StreamReaders
C) OutputStream
D) Writers
E) Readers
F) Streams
57. Low Level Streams read input as bytes and writes as bytes, then select the correct declarations
of Streams.
A) FileInputStream FIS = new FileInputStream("test.txt")
B) File file = new File("test.txt"); FileInputStream FIS = new FileInputStream(file)
C) File file = new File("c:\\"); File file1 = new File(file,"test.txt"); FileOutputStream FOS = new
FileOutputStream(file1);
D) FileInputStream FIS = new FileInputStream("c:\\","test.txt")
58. Choose all valid forms of the argument list for the FileOutputStream constructor shown below:
A) FileOutputStream( FileDescriptor fd )
B) FileOutputStream( String n, boolean a )
C) FileOutputStream( boolean a )
D) FileOutputStream()
E) FileOutputStream( File f )
59. What is the class that has "mode" argument such as "r" or "rw" is required in the constructor:
A) DataInputStream
B) InputStream
C) RandomAccessFile
D) File
60. What is the output displayed by the following code?
import java.io.*;
public class TestIPApp {
public static void main(String args[]) throws IOException {
RandomAccessFile file = new RandomAccessFile("test.txt", "rw");
file.writeBoolean(true);
file.writeInt(123456);
file.writeInt(7890);
file.writeLong(1000000);
file.writeInt(777);
file.writeFloat(.0001f);
file.seek(5);
System.out.println(file.readInt());
file.close();
}
}
Select correct answer:
A) 123456
B) 7890
C) 1000000
D) .0001
Answers
Answer 1:
A) String str[];
C) String str[] = new String[] {"string1", "string2", "string3", "string4", "string5"};
D) String str[] = {"string1","string2", "string3", "string4", "string5"};
Answer 2:
A) final
D) static
Answer 3:
B) Method declarations.
C) Block of code declarations
Answer 4:
A) Class A Constructor followed by Class B Constructor
Answer 5:
A) super(100);
Answer 6:
A) Overridden methods have the same method name and signature
D) Overloaded methods have the same method name and different signature
Answer 7:
C) The values 100,100,100 printed
Answer 8:
B) break middle;
Answer 9:
A) Compile time error
D) MyMethod() cannot throw an exception in MyExp2 class
Answer 10:
A) Compilation error
Answer 11:
A) The garbage collector runs in low memory situations
C) When it runs it releases the memory allocated by an object, which is no more in use.
Answer 12:
A) 1
Answer 13:
B) goto
E) import, package
NOTE: The keywords 'const' and 'goto' are reserved by Java, even though they are not currently used in Java.
For more information at http://java.sun.com/docs/books/jls/html/3.doc.html#229308
Answer 14:
B) new Inner() { }
Answer 15:
A) An anonymous class cannot have any constructors
D) An anonymous class instantiated and declared in the same place.
Answer 16:
B) abstract class A { abstract void Method() ; }
Answer 17:
C) Does not compile
Answer 18:
B) Compiles and runs printing out "HelloHowAreYou"
Answer 19:
A) goto
B) synchronized
C) extends
D) implements
E) this
Answer 20:
C) Exception is thrown
Answer 21:
A) long l = 698.65;
B) float f = 55.8;
Answer 22:
C) -(2^31) to (2^31 - 1)
Answer 23:
0X7, 0x7, 0x07, 0X07
Explanation:
The 7 can be represented any one of the above mentioned answers.
Answer 24:
0 to 2^16-1
Answer 25:
A) int getID()
Answer 26:
A) Compile time error
Answer 27:
B) Java 1.0 and Java 1.1 event handling models are not compatible
C) Event listeners are the objects that implements listener interfaces.
D) You can add multiple listeners to any event source, then there is no guarantee that the listeners will be
notified in the order in which they were added.
Answer 28:
B) 0x77 >>> 1;
C) 0x77 >> 1;
Answer 29:
A) char c = 'a';
B) double d = 45.6;
D) int k = 8;
Answer 30:
A) b instanceof Button
Answer 31:
C) A equals A modulus 5.
Answer 32:
C) No output
Answer 33:
D) The value of s is HelloWorld will be printed on the screen
Answer 34:
B) b1 || b2;
Explanation:
A) This returns false. == is used as comparison operator.
B) This returns true. Because of OR operation.
C) There is no operator like that.
D) This returns false. This is because of AND operation.
NOTE: The operators ||, && are called short-circuit operators. The operator || ( OR Operation ) returns true if
one operand is true without regard to the other operand. The operator && ( AND Operation ) returns false if one
operand is false, without regard to the other operand . In our example b1 is true and b2 is false.
Answer 35:
A) The x value is 20.
Answer 36:
B) By making methods are public and variables as private
Answer 37:
A) public void amethod(String s, int i){}
D) public void Amethod(int i, String s) {}
Answer 38:
D) Base b = new Base(10);
Explanation:
A) This is wrong because there is no matching constructor defined in Derived class.
B) The super keyword suppose to be the first line in the constructor.
C) The this keyword suppose to be first line in the constructor.
D) This is correct because there is matching constructor in Base class.
Answer 39:
C) Static variables can be called using class name.
Answer 40:
A) The compiler error
Answer 41:
A) Threads start() method makes it eligible to run
B) Thread dies after the run() returns
D) A stop() method kills the currently running Thread
Answer 42:
A) A menu item generates an ActionEvent
Answer 43:
A) Frame's default layout manager is BorderLayout
B) Applet's is Flow Layout
C) Panel's is Flow Layout
D) A Dialog is a pop up window and uses BorderLayout as default.
Answer 44:
B) If fill is both, anchor does not make sense.
C) It divides its territory in to an array of cells.
D) While constructing GridBagLayout, you won't tell how many rows and columns the underlying grid has.
Answer 45:
A) gridwidth, gridheight, specifies how many columns and rows to span.
B) gridx, gridy has GridBagConstraints.RELATIVE which adds left to right and top to bottom, still you can specify
gridwidth and gridheight except for last component, which you have to set GridBagConstraints.REMAINDER.
Answer 46:
C) Compiler fails at the time of Math class instantiation
Answer 47:
A) 145.0 followed by -145.0
Answer 48:
A) int a = 10; float f = 10; if ( a = = f) { System.out.println("Equal");}
Answer 49:
A) List
Answer 50:
A) true
Answer 51:
B) Collection
Answer 52:
C) List
Answer 53:
C) c:\source\Ran.test
Answer 54:
A) File f = new File("/","autoexec.bat");
B) DataInputStream d = new DataInputStream(System.in);
C) OutputStreamWriter o = new OutputStreamWriter(System.out);
Answer 55:
A)
InputStreamReader reader = new InputStreamReader(stream, "8859-8");
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
B)
InputStreamReader reader = new InputStreamReader(stream);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
E)
FileReader reader = new FileReader(myfile);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
Answer 56:
A) InputStream
C) OutputStream
Answer 57:
A) FileInputStream FIS = new FileInputStream("test.txt")
B) File file = new File("test.txt"); FileInputStream FIS = new FileInputStream(file)
C) File file = new File("c:\\"); File file1 = new File(file,"test.txt"); FileOutputStream FOS = new
FileOutputStream(file1);
Answer 58:
A) FileOutputStream( FileDescriptor fd )
B) FileOutputStream( String n, boolean a )
E) FileOutputStream( File f )
Answer 59:
C) RandomAccessFile
Answer 60:
B) 7890
JavaBeat 2005, India (www.javabeat.net)
Submit a Site - Directory - Submit Articles
Select all correct declarations, or declaration and initializations of an array?
A) String str[];
B) String str[5] = new String[5];
C) String str[] = new String[] {"string1", "string2", "string3", "string4", "string5"};
D) String str[] = {"string1","string2", "string3", "string4", "string5"};
2. Which of the following are the java keywords?
A) final
B) Abstract
C) Long
D) static
3. The synchronized is used in which of the following?
A) Class declarations.
B) Method declarations.
C) Block of code declarations
D) Variable declarations.
4. What will be printed when you execute the code?
class A {
A() {
System.out.println("Class A Constructor");
}
}
public class B extends A {
B() {
System.out.println("Class B Constructor");
}
public static void main(String args[]) {
B b = new B();
}
}
A) Class A Constructor followed by Class B Constructor
B) Class B Constructor followed by Class A Constructor
C) Compile time error
D) Run time error
5. Given the piece of code, select the correct to replace at the comment line?
class A {
A(int i) { }
}
public class B extends A {
B() {
// xxxxx
}
public static void main(String args[]) {
B b = new B();
}
}
A) super(100);
B) this(100);
C) super();
D) this();
6. Which of the statements are true?
A) Overridden methods have the same method name and signature
B) Overloaded methods have the same method name and signature
C) Overridden methods have the same method name and different signature
D) Overloaded methods have the same method name and different signature
7. What is the output when you execute the following code?
int i = 100;
switch (i) {
case 100:
System.out.println(i);
case 200:
System.out.println(i);
case 300:
System.out.println(i);
}
A) Nothing is printed
B) Compile time error
C) The values 100,100,100 printed
D) Only 100 is printed
8. How can you change the break statement below so that it breaks out of the inner and middle loops
and continues with the next iteration of the outer loop?
outer: for ( int x =0; x < 3; x++ ) {
middle: for ( int y=0; y < 3; y++ ) {
if ( y == 1) {
break;
}
}
}
A) continue middle
B) break middle:
C) break outer:
D) continue
9. What is the result of compiling the following code?
import java.io.*;
class MyExp {
void MyMethod() throws IOException, EOFException {
//............//
}
}
class MyExp1 extends MyExp {
void MyMethod() {
//..........//
}
}
public class MyExp2 extends MyExp1 {
void MyMethod() throws IOException {
//.........//
}
}
A) Compile time error
B) No compile time error
C) Run-Time error
D) MyMethod() cannot declare IOException in MyExp2 class
10. What is the result when you compile the and run the following code?
public class ThrowsDemo {
static void throwMethod() {
System.out.println("Inside throwMethod.");
throw new IllegalAccessException("demo");
}
public static void main(String args[]) {
try {
throwMethod();
} catch (IllegalAccessException e) {
System.out.println("Caught " + e);
}
}
}
A) Compilation error
B) Runtime error
C) Compile successfully, nothing is printed.
D) Inside throwMethod. followed by caught: java.lang.IllegalAccessExcption: demo
11. Which of the following statements about garbage collection are true?
A) The garbage collector runs in low memory situations
B) You can run the garbage collector when ever you want.
C) When it runs, it releases the memory allocated by an object, which is no more in use.
D) Garbage collector immediately runs when you set the references to null.
12. From the following code how many objects are eligible for garbage collection?
String string1 = "Test";
String string2 = "Today";
string1 = null;
string1 = string2;
A) 1
B) 2
C) 3
D) 0
13. Select all correct list of keywords or Java reserved words?
A) superclass
B) goto
C) open
D) integer
E) import, package
F) They are all java keywords
14. Select the correct anonymous inner class declaration ?
A) new Outer.new Inner
B) new Inner() { }
C) new Inner()
D) Outer.new Inner()
15. Which of the following statements are true?
A) An anonymous class cannot have any constructors
B) An anonymous class can only be created within the body of a method
C) An anonymous class can only access static fields of the enclosing class
D) An anonymous class instantiated and declared in the same place.
16. Which of the following class definitions are legal declaration of an abstract class?
A) class A { abstract void Method() {} }
B) abstract class A { abstract void Method() ; }
C) class A { abstract void Method() {System.out.println("Test");} }
D) class abstract A { abstract void Method() {} }
17. What is the result of compiling the following code?
public class Test {
public static void main ( String[] args) {
int value;
value = value + 1;
System.out.println(" The value is : " + value);
}
}
A) Compile and runs with no output
B) Compiles and runs printing out "The value is 1"
C) Does not compile
D) Compiles but generates run time error
18. What is the result of compiling the following code? When you run like given below?
java Test Hello How Are You
public class Test {
public static void main ( String[] args) {
for ( int i = 0; i < args.length; i++)
System.out.print(args[i]);
}
}
A) Compile and runs with no output
B) Compiles and runs printing out "HelloHowAreYou"
C) Does not compile
D) Compiles but generates run time error
19. Which are the following are java keywords ?
A) goto
B) synchronized
C) extends
D) implements
E) this
F) NULL
20. What is the output of the following code?
public class TestLocal {
public static void main(String args[]) {
String s[] = new String[6];
System.out.print(s[6]);
}
}
A) A null is printed
B) Compile time error
C) Exception is thrown
D) null followed by 0 is printed on the screen
21. Which of the following assignment statements is invalid?
A) long l = 698.65;
B) float f = 55.8;
C) double d = 0x45876;
D) All of the above
22. What is the numeric range for a Java int data type?
A) 0 to (2^32)
B) -(2^31) to (2^31)
C) -(2^31) to (2^31 - 1)
D) -(2^15) to (2^15 - 1)
23. How to represent number 7 as hexadecimal literal?
-----------
24. ------- is the range of the char data type?
25. Which of the following method returns the ID of an event?
A) int getID()
B) String getSource()
C) int returnID()
D) int eventID()
26. Which of the following are correct, if you compile the following code?
public class CloseWindow extends Frame implements WindowListener {
public CloseWindow() {
addWindowListener(this); // This is listener registration
setSize(300, 300);
setVisible(true);
}
public void windowClosing(WindowEvent e) {
System.exit(0);
}
public static void main(String args[]) {
CloseWindow CW = new CloseWindow();
}
}
A) Compile time error
B) Run time error
C) Code compiles but Frame does not listen to WindowEvents
D) Compile and runs successfully.
27. Select all correct answers from the following?
A) Java 1.0 event handling is compatible with event delegation model in Java 1.1
B) Java 1.0 and Java 1.1 event handling models are not compatible
C) Event listeners are the objects that implements listener interfaces.
D) You can add multiple listeners to any event source, then there is no guarantee that the listeners will be
notified in the order in which they were added.
28. Given the byte with a value of 01110111, which of the following statements will produce
00111011?
A) 0x77 << 1;
B) 0x77 >>> 1;
C) 0x77 >> 1;
D) None of the above
29. Which of the following will compile without error?
A) char c = 'a';
B) double d = 45.6;
C) int i = d;
D) int k = 8;
30. Which of the following returns true when replace with XXXXXXXXX?
public class TestType {
public static void main(String args[] ) {
Button b = new Button("BUTTON");
if( XXXXXXXXX) {
System.out.print("This is an instance of Button");
}
}
}
A) b instanceof Button
B) Button instanceof b
C) b == Button
D) Button == (Object) b
31. The statement X %= 5, can best described as?
A) A equals a divided by 5;
B) A equals A in 5 digit percentage form
C) A equals A modulus 5.
D) None of the above
32. What will happen when you attempt to compile and run the following code?
public class MyClass {
public static void main(String args[]) {
String s1 = new String("Test One");
String s2 = new String("Test One");
if ( s1== s2 ) {
System.out.println("Both are equal");
}
Boolean b = new Boolean(true);
Boolean b1 = new Boolean(false);
if ( b.equals(b1) ) {
System.out.println("These wrappers are equal");
}
}
}
A) Compile time error
B) Runtime error.
C) No output
D) These wrappers are equal
33. What is the result when you try to compile and run the following code?
public class TestBit {
public static void main(String args[]) {
String s = "HelloWorld";
if ((s != null) && (s.length() > 6))
System.out.println("The value of s is " + s );
}
}
A) Compile time error
B) Runtime error
C) No output is printed
D) The value of s is HelloWorld will be printed on the screen
34. Given the following declaration which of the following statements equals to true
boolean b1 = true;
boolean b2 = false;
A) b1 == b2;
B) b1 || b2;
C) b1 |& b2;
D) b1 && b2;
35. What is the result of the following code?
public class MyTest {
int x = 30;
public static void main(String args[]) {
int x = 20;
MyTest ta = new MyTest();
ta.Method(x);
System.out.println("The x value is " + x);
}
void Method(int y){
int x = y * y;
}
}
A) The x value is 20.
B) The x value is 30.
C) The x value is 400.
D) The x value is 600.
36. How can you implement encapsulation.
A) By making methods private and variable private
B) By making methods are public and variables as private
C) Make all variable are public and access them using methods
D) Making all methods and variables as protected.
37. Given the following class definition, which of the following methods could be legally placed after
the comment ?
public class Test{
public void amethod(int i, String s){}
//Here
}
A) public void amethod(String s, int i){}
B) public int amethod(int i, String s){}
C) public void amethod(int i, String mystring){}
D) public void Amethod(int i, String s) {}
38. Given the following class definition which of the following can be legally placed after the
comment line?
class Base{
public Base(int i){}
}
public class Derived extends Base{
public static void main(String arg[]){
Derived d = new Derived(10);
}
Derived(int i){
super(i);
}
Derived(String s, int i){
this(i);
//Here
}
}
A) Derived d = new Derived();
B) super();
C) this("Hello",10);
D) Base b = new Base(10);
39. Which of the following statements are true?
A) An inner class cannot be defined as private.
B) Static methods can be overridden by static methods only.
C) Static variables can be called using class name.
D) Non static variables can be called using class name.
40. What does the following code do?
public class RThread implements Runnable {
public void run (String s ) {
System.out.println ("Executing Runnable Interface Thread");
}
public static void main ( String args []) {
RThread rt = new RThread ( );
Thread t = new Thread (rt);
t.start ( );
}
}
A) The compiler error
B) The runtime error
C) Compiles and prints "Executing Runnable Interface Thread" on the screen
D) Compiles and does not print any thing on the screen
41. Which statements are true?
A) Threads start() method makes it eligible to run
B) Thread dies after the run() returns
C) A dead Thread can be started again.
D) A stop() method kills the currently running Thread
42. Which of the following are true?
A) A menu item generates an ActionEvent
B) A menu item generates ItemEvent
C) A menu item generates KeyEvent
D) A menu item generates TextEvent
43. Default Layout Managers are concerned ?
A) Frame's default layout manager is BorderLayout
B) Applet's is FlowLayout
C) Panel's is FlowLayout
D) A Dialog is a pop up window and uses BorderLayout as default.
44. Which statements are true about GridBagLayout ?
A) Weight x and weight y should be 0.0 and 1.0
B) If fill is both, anchor does not make sense.
C) It divides its territory in to an array of cells.
D) While constructing GridBagLayout, you won't tell how many rows and columns the underlying grid has.
45. Which of the following are true?
A) gridwidth, gridheight, specifies how many columns and rows to span.
B) gridx, gridy has GridBagConstraints.RELATIVE which adds left to right and top to bottom, still you can specify
gridwidth and gridheight except for last component, which you have to set GridBagConstraints.REMAINDER.
46. Which of the following statements are true about the fragment below?
import java.lang.Math;
public class Test {
public static void main(String args[]) {
Math m = new Math();
System.out.println(m.abs(2.6);
}
}
A) Compiler fails at line 1
B) Compiler fails at line 2
C) Compiler fails at the time of Math class instantiation
D) Compiler succeeds.
47. What will be the output of the following line?
public class TestFC {
public static void main(String args[]) {
System.out.println(Math.floor(145.1));
System.out.println(Math.ceil(-145.4));
}
}
A) 145.0 followed by -145.0
B) 150.0 followed by -150.0
C) 145.1 followed by -145.4
48. Which of the following prints "Equal"
A) int a = 10; float f = 10;
if ( a = = f) { System.out.println("Equal");}
B) Integer i = new Integer(10);
Double d = new Double(10);
if ( i = =d) { System.out.println("Equal");}
C) Integer a = new Integer(10);
int b = 10;
if ( a = = b) { System.out.println("Equal");}
D) String a = new String("10");
String b = new String("10");
if ( a = = b) { System.out.println("Equal");}
49. Which of the following implement clear notion of one item follows another (order)?
A) List
B) Set
C) Map
D) Iterator
50. Collection interface iterator method returns Iterator(like Enumerator), through you can traverse
a collection from start to finish and safely remove elements.
A) true
B) false
51. Which of the following places no constraints on the type of elements, order of elements, or
repetition of elements with in the collection.?
A) List
B) Collection
C) Map
D) Set
52. Which of the following gives Stack and Queue functionality.?
A) Map
B) Collection
C) List
D) Set
53. If you run the following code on a PC from the directory c:\source:
import java.io.*;
class Path {
public static void main(String[] args) throws Exception {
File file = new File("Ran.test");
System.out.println(file.getAbsolutePath());
}
}
What do you expect the output to be? Select the one right answer.
A) Ran.test
B) source\Ran.test
C) c:\source\Ran.test
D) c:\source
E) null
54. Which of the following will compile without error?
A) File f = new File("/","autoexec.bat");
B) DataInputStream d = new DataInputStream(System.in);
C) OutputStreamWriter o = new OutputStreamWriter(System.out);
D) RandomAccessFile r = new RandomAccessFile("OutFile");
55. You have an 8-bit file using the character set defined by ISO 8859-8. You are writing an
application to display this file in a TextArea. The local encoding is already set to 8859-8. How can
you write a chunk of code to read the first line from this file?
You have three variables accessible to you:
myfile is the name of the file you want to read
stream is an InputStream object associated with this file
s is a String object
Select all valid answers.
A)
InputStreamReader reader = new InputStreamReader(stream, "8859-8");
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
B)
InputStreamReader reader = new InputStreamReader(stream);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
C)
InputStreamReader reader = new InputStreamReader(myfile, "8859-8");
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
D)
InputStreamReader reader = new InputStreamReader(myfile);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
E)
FileReader reader = new FileReader(myfile);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
56. Which of the following used to read and write to network sockets, which are super classes of
Low level streams?
A) InputStream
B) StreamReaders
C) OutputStream
D) Writers
E) Readers
F) Streams
57. Low Level Streams read input as bytes and writes as bytes, then select the correct declarations
of Streams.
A) FileInputStream FIS = new FileInputStream("test.txt")
B) File file = new File("test.txt"); FileInputStream FIS = new FileInputStream(file)
C) File file = new File("c:\\"); File file1 = new File(file,"test.txt"); FileOutputStream FOS = new
FileOutputStream(file1);
D) FileInputStream FIS = new FileInputStream("c:\\","test.txt")
58. Choose all valid forms of the argument list for the FileOutputStream constructor shown below:
A) FileOutputStream( FileDescriptor fd )
B) FileOutputStream( String n, boolean a )
C) FileOutputStream( boolean a )
D) FileOutputStream()
E) FileOutputStream( File f )
59. What is the class that has "mode" argument such as "r" or "rw" is required in the constructor:
A) DataInputStream
B) InputStream
C) RandomAccessFile
D) File
60. What is the output displayed by the following code?
import java.io.*;
public class TestIPApp {
public static void main(String args[]) throws IOException {
RandomAccessFile file = new RandomAccessFile("test.txt", "rw");
file.writeBoolean(true);
file.writeInt(123456);
file.writeInt(7890);
file.writeLong(1000000);
file.writeInt(777);
file.writeFloat(.0001f);
file.seek(5);
System.out.println(file.readInt());
file.close();
}
}
Select correct answer:
A) 123456
B) 7890
C) 1000000
D) .0001
Answers
Answer 1:
A) String str[];
C) String str[] = new String[] {"string1", "string2", "string3", "string4", "string5"};
D) String str[] = {"string1","string2", "string3", "string4", "string5"};
Answer 2:
A) final
D) static
Answer 3:
B) Method declarations.
C) Block of code declarations
Answer 4:
A) Class A Constructor followed by Class B Constructor
Answer 5:
A) super(100);
Answer 6:
A) Overridden methods have the same method name and signature
D) Overloaded methods have the same method name and different signature
Answer 7:
C) The values 100,100,100 printed
Answer 8:
B) break middle;
Answer 9:
A) Compile time error
D) MyMethod() cannot throw an exception in MyExp2 class
Answer 10:
A) Compilation error
Answer 11:
A) The garbage collector runs in low memory situations
C) When it runs it releases the memory allocated by an object, which is no more in use.
Answer 12:
A) 1
Answer 13:
B) goto
E) import, package
NOTE: The keywords 'const' and 'goto' are reserved by Java, even though they are not currently used in Java.
For more information at http://java.sun.com/docs/books/jls/html/3.doc.html#229308
Answer 14:
B) new Inner() { }
Answer 15:
A) An anonymous class cannot have any constructors
D) An anonymous class instantiated and declared in the same place.
Answer 16:
B) abstract class A { abstract void Method() ; }
Answer 17:
C) Does not compile
Answer 18:
B) Compiles and runs printing out "HelloHowAreYou"
Answer 19:
A) goto
B) synchronized
C) extends
D) implements
E) this
Answer 20:
C) Exception is thrown
Answer 21:
A) long l = 698.65;
B) float f = 55.8;
Answer 22:
C) -(2^31) to (2^31 - 1)
Answer 23:
0X7, 0x7, 0x07, 0X07
Explanation:
The 7 can be represented any one of the above mentioned answers.
Answer 24:
0 to 2^16-1
Answer 25:
A) int getID()
Answer 26:
A) Compile time error
Answer 27:
B) Java 1.0 and Java 1.1 event handling models are not compatible
C) Event listeners are the objects that implements listener interfaces.
D) You can add multiple listeners to any event source, then there is no guarantee that the listeners will be
notified in the order in which they were added.
Answer 28:
B) 0x77 >>> 1;
C) 0x77 >> 1;
Answer 29:
A) char c = 'a';
B) double d = 45.6;
D) int k = 8;
Answer 30:
A) b instanceof Button
Answer 31:
C) A equals A modulus 5.
Answer 32:
C) No output
Answer 33:
D) The value of s is HelloWorld will be printed on the screen
Answer 34:
B) b1 || b2;
Explanation:
A) This returns false. == is used as comparison operator.
B) This returns true. Because of OR operation.
C) There is no operator like that.
D) This returns false. This is because of AND operation.
NOTE: The operators ||, && are called short-circuit operators. The operator || ( OR Operation ) returns true if
one operand is true without regard to the other operand. The operator && ( AND Operation ) returns false if one
operand is false, without regard to the other operand . In our example b1 is true and b2 is false.
Answer 35:
A) The x value is 20.
Answer 36:
B) By making methods are public and variables as private
Answer 37:
A) public void amethod(String s, int i){}
D) public void Amethod(int i, String s) {}
Answer 38:
D) Base b = new Base(10);
Explanation:
A) This is wrong because there is no matching constructor defined in Derived class.
B) The super keyword suppose to be the first line in the constructor.
C) The this keyword suppose to be first line in the constructor.
D) This is correct because there is matching constructor in Base class.
Answer 39:
C) Static variables can be called using class name.
Answer 40:
A) The compiler error
Answer 41:
A) Threads start() method makes it eligible to run
B) Thread dies after the run() returns
D) A stop() method kills the currently running Thread
Answer 42:
A) A menu item generates an ActionEvent
Answer 43:
A) Frame's default layout manager is BorderLayout
B) Applet's is Flow Layout
C) Panel's is Flow Layout
D) A Dialog is a pop up window and uses BorderLayout as default.
Answer 44:
B) If fill is both, anchor does not make sense.
C) It divides its territory in to an array of cells.
D) While constructing GridBagLayout, you won't tell how many rows and columns the underlying grid has.
Answer 45:
A) gridwidth, gridheight, specifies how many columns and rows to span.
B) gridx, gridy has GridBagConstraints.RELATIVE which adds left to right and top to bottom, still you can specify
gridwidth and gridheight except for last component, which you have to set GridBagConstraints.REMAINDER.
Answer 46:
C) Compiler fails at the time of Math class instantiation
Answer 47:
A) 145.0 followed by -145.0
Answer 48:
A) int a = 10; float f = 10; if ( a = = f) { System.out.println("Equal");}
Answer 49:
A) List
Answer 50:
A) true
Answer 51:
B) Collection
Answer 52:
C) List
Answer 53:
C) c:\source\Ran.test
Answer 54:
A) File f = new File("/","autoexec.bat");
B) DataInputStream d = new DataInputStream(System.in);
C) OutputStreamWriter o = new OutputStreamWriter(System.out);
Answer 55:
A)
InputStreamReader reader = new InputStreamReader(stream, "8859-8");
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
B)
InputStreamReader reader = new InputStreamReader(stream);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
E)
FileReader reader = new FileReader(myfile);
BufferedReader buffer = new BufferedReader(reader);
s = buffer.readLine();
Answer 56:
A) InputStream
C) OutputStream
Answer 57:
A) FileInputStream FIS = new FileInputStream("test.txt")
B) File file = new File("test.txt"); FileInputStream FIS = new FileInputStream(file)
C) File file = new File("c:\\"); File file1 = new File(file,"test.txt"); FileOutputStream FOS = new
FileOutputStream(file1);
Answer 58:
A) FileOutputStream( FileDescriptor fd )
B) FileOutputStream( String n, boolean a )
E) FileOutputStream( File f )
Answer 59:
C) RandomAccessFile
Answer 60:
B) 7890
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