Java 6 Test
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Pearlox Corp. Java 6 Test
- 1.What will be the output if you compile and run the following code ?(Choose the correct answer)public class test { public static void main(String args[]) { String str1="abc"; String str2="def"; String str3=str1.concat(str2); str1.concat(str2); System.out.println(str1); }}
- A.
Abc
- B.
Def
- C.
Abcabc
- D.
Abcdef
- E.
Defabc
- 2.The number of characters in an object of a class String is given by(Choose the correct answer)
- A.
The member variable called size
- B.
The member variable called length
- C.
The method size() returns the number of characters.
- D.
The method length() returns the number of characters.
- E.
The method getSize() returns the number of characters.
- 3.Which method defined in Integer class can be used to convert an Integer object to primitive int type.(Choose the correct answer)
- A.
ValueOf
- B.
IntValue
- C.
GetInt
- D.
GetInteger
- E.
ToInt
- 4.Which are valid Java keywords.(Choose all that apply)
- A.
Distinct
- B.
Synchronized
- C.
Volatile
- D.
Goto
- E.
Construct
- 5.What is the number of bytes used by the primitive type long. (Select the best answer)
- A.
8
- B.
16
- C.
32
- D.
64
- E.
128
- 6.What is the name of the Collection interface used to represent elements in a sequence (in a particular order). (Choose the correct answer)
- A.
Collection
- B.
Set
- C.
List
- D.
Map
- E.
HashMap
- 7.Which of the following statements about arrays are true.(Choose all that apply)
- A.
Arrays in Java are objects.
- B.
It is not possible to assign one array to another.
- C.
Array elements are indexed from 1 to size of the array.
- D.
If a method tries to access an array element beyond its range, a compile warning is generated.
- E.
Arrays size must be specified at creation time.
- 8.What will be the output if you compile and run the following code ?public class Main {public static void main(String[] args) { int i1=1; switch(i1){ case 1: System.out.println("one"); case 2: System.out.println("two"); case 3: System.out.println("three");}}}
- A.
One two three
- B.
One
- C.
One two
- D.
Compile error.
- E.
None of the above
- 9.What will be the output if you compile and run the following code ?public class Main { public static void main(String[] args) { char c = 'a'; switch(c){ case 1: System.out.println("one");break; case 'a': System.out.println("two");break; case 3: System.out.println("three"); } }}
- A.
One two three
- B.
One
- C.
Two
- D.
Three
- E.
Compile error.
- 10.What will be the output if you compile and run the following code ?public class Main { public static void main(String[] arg) { method1(arg); } public void method1(String... arguments) { System.out.println(arguments); }}
- A.
Cannot make a static reference to the non-static method method1.
- B.
Compile error method main is not correct
- C.
Compile error method method1 is not correct
- D.
Method1 must be declared with String not String...
- E.
This code compiles and run without errors.
- 11.What will be the output if you compile and run the following code ?public class Main{ private static int i; public static void main(String[] args){ System.out.println(i); }}
- A.
Error, Variable i may not have been initialized
- B.
0
- C.
1
- D.
Null
- E.
None of the above
- 12.What will be the output if you compile and run the following code ?public class Main { public static void main(String[] args){ int vest[]=new int[]{1,2,3}; System.out.println(vest[1]); }}
- A.
1
- B.
Error vest is referenced before it is initialized
- C.
2
- D.
Error: size of array must be defined
- E.
None of the above
- 13.What will be the output if you compile and run the following code ?public class Test { public static void main(String[] arg){ int anar[]=new int[5]; System.out.println(anar[0]); }}
- A.
Error: anar is referenced before it is initialized
- B.
Null
- C.
0
- D.
5
- E.
4
- 14.What will be the output if you compile and run the following code ?abstract class Super { abstract void amethod(); static int i;}public class Test extends Super { public static void main(String... args){ int[] arr = new int[5]; for(i=0;i < arr.length;i++) System.out.println(arr[i]); }}
- A.
0 1 2 3 4 is printed
- B.
Compile error, arr is used before it is initialized
- C.
Compile error, Test must be declared abstract
- D.
ArrayIndexOutOfBoundes Exception
- E.
None of the above.
- 15.What will be the output if you compile and run the following code ?int i=1; switch (i) { case 0: System.out.println("number"); break; case 1: System.out.println("one"); case 5: System.out.println("two");case 10: System.out.println("three"); default: System.out.println("default"); }
- A.
One
- B.
One, default
- C.
One, two, three, default
- D.
Default
- E.
Two
- 16.What will be the output if you compile and run the following code ?int h=15;switch (h) { default: System.out.println("default"); case 20: System.out.println("20"); break; case 21: System.out.println("21"); case 22: System.out.println("22"); }
- A.
Default
- B.
Default, 20
- C.
20, 21
- D.
No output is displayed
- E.
Compiler error default must be defined last.
- 17.Which of the following statements are correct ?
- A.
Methods cannot be overriden to be more restrictive for example private
- B.
Static methods cannot be overloaded
- C.
Private methods cannot be overloaded
- D.
Abstract methods cannot be overriden in subclasses.
- E.
Final methods cannot be overriden in subclasses.
- 18.
- A.
Void method1(int k) throws Exception {}
- B.
Void method1(long i)throws Exception {}
- C.
void method1(long i){}
- D.
Public void method1(int j) throws Exception {}
- E.
Public void method1(double d) throws Exception {}
- 19.What will be the output if you compile and run the following code ?String str=new String("honey");int begin=1;int end=3;System.out.println(str.substring(begin,end));
- A.
Hon
- B.
Ho
- C.
On
- D.
Runtime Exception is thrown
- E.
None of the above
- 20.Given the following declarationsString s1=new String("1")String s2=new String("2");String s3=new String("true");String s3=new String("false");Which of the following are legal operations?
- A.
S3=s1 + s2;
- B.
S3=s1-s2;
- C.
S3=s1 & s2;
- D.
S3=s1 && s2
- E.
S3=s3 && s4
- 21.What will happen when you attempt to compile and run the following code?class TestRunnable implements Runnable { int k = 0; public int run() { while (true) { k++; System.out.print("k=" + k); } return 50; }}
- A.
It will compile fine.
- B.
It will not compile.
- C.
The code will compile but throws an exception at runtime.
- D.
Comipler errors because while cannot take a parameter of true.
- E.
None of the above.
- 22.Which of the following statements about this code are true?class Testing extends Thread{ public void run(){ for(int i =0; i < 2; i++){ System.out.println(i); } } }public class Sub{ public static void main(String[] args){ Sub m = new Sub(); m.go(new Testing()); } public void go(Testing t){ t.start(); } }
- A.
This program compiles and run fine, but it has no output.
- B.
Compiler error, class Testing has no start method
- C.
Compiles fine and output 0 followed by 1
- D.
Compiles fine but fails at runtime.
- E.
Compiler error, class Testing doesnt provide legal override for method run.
- 23.What will happen if you attempt to compile and run the following code?.public class Main { static int j = 20; public static void main(String[] args) { int i = 10; Main m = new Main(); m.m1(i); System.out.println(i); System.out.println(j); } public void m1(int x) { x = x * 2; j = j * 2; }}
- A.
Compiler error, static access from non static context.
- B.
20 and 40
- C.
10 and 40
- D.
10 and 20
- E.
20 and 20
- 24.What will happen if you attempt to compile and run the following code?.public class Main { public static void main(String[] args) { Main m = new Main(); m.m1(); } public void m1() { int ii = 012; System.out.println(ii); }}.............
- 25.You have a requirement to create a class that will store unique object elements. And you do not need to sort these elements.Which interface might be most suitable to meet your requirement?
- A.
Set
- B.
List
- C.
Map
- D.
ArrayList
- E.
Collection
- 26.What will happen if you attempt to compile and run the following code?.public class Main { private int ii; public static void main(String[] args) { Main m = new Main(); m.m1(); } public static void m1() { System.out.println(ii); }}
- A.
A value of 0 will be printed to the standard output
- B.
Nothing will be printed
- C.
Compiler error occured
- D.
A Compiler error occured complaining of the scope of variable ii
- E.
Runtime exception is thrown.
- 27.Which declares a valid main method. (Choose all that apply)
- A.
Public static void Main(String[] args)
- B.
Static void main(String args...)
- C.
public static void main(String... args)
- D.
Public void main(String args)
- E.
Public static void main(String arguments[])
- 28.Given the following declarations, which of the assignments given below would compile.(Choose all that apply)int k = 20;boolean b = true;float f = 2.5F;double d = 2.5;
- A.
B = (boolean) k;
- B.
F = d;
- C.
D = k;
- D.
K = (int)5.5D;
- E.
F = 2.8;
- 29.Which defines a legal method declaration ?(Choose all that apply)
- A.
Void m1() throws Exception{}
- B.
Void m2(int) throw Exception{}
- C.
Private m3() {}
- D.
Volatile m4() throws IOException{}
- E.
Private synchronized void m5() throws Exception {}
- 30.Which are legal identifier names in Java. (Choose all that apply)
- A.
True
- B.
$a_
- C.
1a
- D.
A1
- E.
_this_is_a_lengthy_variable_name_in_java_
- 31.void method() { }Which of the following declares a legal override of this method in a sub class.(Choose all that apply)
- A.
Void method() { }
- B.
Int method() { return 0;}
- C.
Void method(int i) { }
- D.
private void method() { }
- E.
Protected void method() { }
- 32.Which keyword when applied on a method indicates that only one thread can execute this method at a time. (Choose the correct answer)
- A.
Transient
- B.
Volatile
- C.
Synchronized
- D.
Native
- E.
Static
- 33.Which of these statements are true. (Choose all that apply)
- A.
For each try block there must be at least one catch block defined
- B.
A try block may be followed by any number of finally blocks
- C.
A try block must be followed by at least one finally or catch block
- D.
If both catch and finally blocks are defined, catch block must appear before finally
- E.
A try block may be defined inside a catch block
- 34.What gets printed when the following program is compiled and run? (Choose the correct answer)class Main { public static void main(String[] args) { int i; do { i++; } while(i < 0); System.out.println(i); }}
- A.
The program does not compile as i is not initialized
- B.
The program compiles but does not run.
- C.
The program compiles and runs but does not print anything
- D.
The program prints 0
- E.
The program prints 1
- 35.What gets printed when the following program is compiled and run? (Choose the correct answer)class Main { static int i; public static void main(String... args) { while (i < 0) { i--; } System.out.println(i); }}
- A.
The program does not compile as i is not initialized
- B.
The program compiles but does not run
- C.
The program compiles and runs but does not print anything
- D.
The program prints 0
- E.
The program prints 1
- 36.What gets printed when the following program is compiled and run? public class Main { public void m1(Object o) { System.out.println("Object"); } public void m1(String s) { System.out.println("String"); } public static void main(String args[]) { Main m = new Main(); m.m1(null); }}
- A.
The code does not compile
- B.
The code compiles fine and prints "Object"
- C.
The code compiles fine and prints "String"
- D.
The code throws an Exception at Runtime
- E.
The output cannot be determined
- 37.What kind of thread is the Garbage collector thread?
- A.
Daemon thread
- B.
Kernel thread
- C.
User thread
- D.
Worker thread
- E.
Hyper threaed
- 38.What kind of objects is StringBuffer ?
- A.
Reference object
- B.
Primitive object
- C.
Mutable object
- D.
Immutable object
- E.
Oriented object
- 39.What Locale object represent?
- A.
Geographical
- B.
Political
- C.
Cultural region
- D.
Language
- E.
All the above
- 40.What is the best way to findout the time/memory consuming process?
- A.
Using profiler
- B.
Using logger
- C.
Using debuger
- D.
Using sysstat
- E.
Using analizer
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