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Tuesday, August 31, 2010

Previous Year's Papers OF IPU

To Download Previous year papers:
Follow the link below...

Feel free to appreciate my work...

Lecture Plan of CSE 5th Sem

To Download Lecture Plan of 5th Semester CSE Branch:
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For any other material:
feel free to request in Comments

Saturday, August 14, 2010

Operators and assignments in Java

1. Unary operators

1.1 Increment and Decrement operators ++ --

We have postfix and prefix notation. In post-fix notation value of the variable/expression is modified after the value is taken for the execution of statement. In prefix notation, value of the variable/expression is modified before the value is taken for the execution of statement.

x = 5; y = 0; y = x++; Result will be x = 6, y = 5

x = 5; y = 0; y = ++x; Result will be x = 6, y = 6

Implicit narrowing conversion is done, when applied to byte, short or char.

1.2 Unary minus and unary plus + -

+ has no effect than to stress positivity.

- negates an expression's value. (2's complement for integral expressions)

1.3 Negation !

Inverts the value of a boolean expression.

1.4 Complement ~

Inverts the bit pattern of an integral expression. (1's complement - 0s to 1s and 1s to 0s)

Cannot be applied to non-integral types.

1.5 Cast ()

Persuades compiler to allow certain assignments. Extensive checking is done at compile and runtime to ensure type-safety.

2. Arithmetic operators - *, /, %, +, -

· Can be applied to all numeric types.

· Can be applied to only the numeric types, except '+' - it can be applied to Strings as well.

· All arithmetic operations are done at least with 'int'. (If types are smaller, promotion happens. Result will be of a type at least as wide as the wide type of operands)

· Accuracy is lost silently when arithmetic overflow/error occurs. Result is a nonsense value.

· Integer division by zero throws an exception.

· % - reduce the magnitude of LHS by the magnitude of RHS. (continuous subtraction)

· % - sign of the result entirely determined by sign of LHS

· 5 % 0 throws an ArithmeticException.

· Floating point calculations can produce NaN (square root of a negative no) or Infinity ( division by zero). Float and Double wrapper classes have named constants for NaN and infinities.

· NaN's are non-ordinal for comparisons. x == Float.NaN won't work. Use Float.IsNaN(x) But equals method on wrapper objects(Double or Float) with NaN values compares Nan's correctly.

· Infinities are ordinal. X == Double.POSITIVE_INFINITY will give expected result.

· + also performs String concatenation (when any operand in an expression is a String). The language itself overloads this operator. toString method of non-String object operands are called to perform concatenation. In case of primitives, a wrapper object is created with the primitive value and toString method of that object is called. ("Vel" + 3 will work.)

· Be aware of associativity when multiple operands are involved.

System.out.println( 1 + 2 + "3" ); // Prints 33

System.out.println( "1" + 2 + 3 ); // Prints 123

3. Shift operators - <<, >>, >>>

· << performs a signed left shift. 0 bits are brought in from the right. Sign bit (MSB) is preserved. Value becomes old value * 2 ^ x where x is no of bits shifted.

· >> performs a signed right shift. Sign bit is brought in from the left. (0 if positive, 1 if negative. Value becomes old value / 2 ^ x where x is no of bits shifted. Also called arithmetic right shift.

· >>> performs an unsigned logical right shift. 0 bits are brought in from the left. This operator exists since Java doesn't provide an unsigned data type (except char). >>> changes the sign of a negative number to be positive. So don't use it with negative numbers, if you want to preserve the sign. Also don't use it with types smaller than int. (Since types smaller than int are promoted to an int before any shift operation and the result is cast down again, so the end result is unpredictable.)

· Shift operators can be applied to only integral types.

· -1 >> 1 is -1, not 0. This differs from simple division by 2. We can think of it as shift operation rounding down.

· 1 << 31 will become the minimum value that an int can represent. (Value becomes negative, after this operation, if you do a signed right shift sign bit is brought in from the left and the value remains negative.)

· Negative numbers are represented in two's complement notation. (Take one's complement and add 1 to get two's complement)

· Shift operators never shift more than the number of bits the type of result can have. ( i.e. int 32, long 64) RHS operand is reduced to RHS % x where x is no of bits in type of result.

int x;

x = x >> 33; // Here actually what happens is x >> 1

4. Comparison operators - all return boolean type.

4.1 Ordinal comparisons - <, <=, > , >=

· Only operate on numeric types. Test the relative value of the numeric operands.

· Arithmetic promotions apply. char can be compared to float.

4.2 Object type comparison - instanceof

· Tests the class of an object at runtime. Checking is done at compile and runtime same as the cast operator.

· Returns true if the object denoted by LHS reference can be cast to RHS type.

· LHS should be an object reference expression, variable or an array reference.

· RHS should be a class (abstract classes are fine), an interface or an array type, castable to LHS object reference. Compiler error if LHS & RHS are unrelated.

· Can't use java.lang.Class or its String name as RHS.

· Returns true if LHS is a class or subclass of RHS class

· Returns true if LHS implements RHS interface.

· Returns true if LHS is an array reference and of type RHS.

· x instanceof Component[] - legal.

· x instanceof [] - illegal. Can't test for 'any array of any type'

· Returns false if LHS is null, no exceptions are thrown.

· If x instanceof Y is not allowed by compiler, then Y y = (Y) x is not a valid cast expression. If x instanceof Y is allowed and returns false, the above cast is valid but throws a ClassCastException at runtime. If x instanceof Y returns true, the above cast is valid and runs fine.

4.3 Equality comparisons - ==, !=

· For primitives it's a straightforward value comparison. (promotions apply)

· For object references, this doesn't make much sense. Use equals method for meaningful comparisons. (Make sure that the class implements equals in a meaningful way, like for X.equals(Y) to be true, Y instance of X must be true as well)

· For String literals, == will return true, this is because of compiler optimization.

5. Bit-wise operators - &, ^, |

· Operate on numeric and boolean operands.

· & - AND operator, both bits must be 1 to produce 1.

· | - OR operator, any one bit can be 1 to produce 1.

· ^ - XOR operator, any one bit can be 1, but not both, to produce 1.

· In case of booleans true is 1, false is 0.

· Can't cast any other type to boolean.

6. Short-circuit logical operators - &&, ||

· Operate only on boolean types.

· RHS might not be evaluated (hence the name short-circuit), if the result can be determined only by looking at LHS.

· false && X is always false.

· true || X is always true.

· RHS is evaluated only if the result is not certain from the LHS.

· That's why there's no logical XOR operator. Both bits need to be known to calculate the result.

· Short-circuiting doesn't change the result of the operation. But side effects might be changed. (i.e. some statements in RHS might not be executed, if short-circuit happens. Be careful)

7. Ternary operator

· Format a = x ? b : c ;

· x should be a boolean expression.

· Based on x, either b or c is evaluated. Both are never evaluated.

· b will be assigned to a if x is true, else c is assigned to a.

· b and c should be assignment compatible to a.

· b and c are made identical during the operation according to promotions.

8. Assignment operators.

· Simple assignment =.

· op= calculate and assign operators extended assignment operators.

· *=, /=, %=, +=, -=

· x += y means x = x + y. But x is evaluated only once. Be aware.

· Assignment of reference variables copies the reference value, not the object body.

· Assignment has value, value of LHS after assignment. So a = b = c = 0 is legal. c = 0 is executed first, and the value of the assignment (0) assigned to b, then the value of that assignment (again 0) is assigned to a.

· Extended assignment operators do an implicit cast. (Useful when applied to byte, short or char)

byte b = 10;

b = b + 10; // Won't compile, explicit cast required since the expression evaluates to an int

b += 10; // OK, += does an implicit cast from int to byte

9. General

· In Java, No overflow or underflow of integers happens. i.e. The values wrap around. Adding 1 to the maximum int value results in the minimum value.

· Always keep in mind that operands are evaluated from left to right, and the operations are executed in the order of precedence and associativity.

· Unary Postfix operators and all binary operators (except assignment operators) have left to right assoiciativity.

· All unary operators (except postfix operators), assignment operators, ternary operator, object creation and cast operators have right to left assoiciativity.

· Inspect the following code.

public class Precedence {

final public static void main(String args[]) {

int i = 0;

i = i++;

i = i++;

i = i++;

System.out.println(i); // prints 0, since = operator has the lowest precedence.

int array[] = new int[5];

int index = 0;

array[index] = index = 3; // 1st element gets assigned to 3, not the 4th element

for (int c = 0; c < array.length; c++)


System.out.println("index is " + index); // prints 3



Type of Operators



Postfix operators

[] . (parameters) ++ --

Left to Right

Prefix Unary operators

++ -- + - ~ !

Right to Left

Object creation and cast

new (type)

Right to Left


* / %

Left to Right


+ -

Left to Right


>> >>> <<

Left to Right


< <= > >= instanceof

Left to Right


== !=

Left to Right

Bit-wise/Boolean AND


Left to Right

Bit-wise/Boolean XOR


Left to Right

Bit-wise/Boolean OR


Left to Right

Logical AND (Short-circuit or Conditional)


Left to Right

Logical OR (Short-circuit or Conditional)


Left to Right


? :

Right to Left


= += -= *= /= %= <<= >>= >>>= &= ^= |=

Right to Left

Friday, August 13, 2010

Serial Number Windows XP Pro SP1,SP2,SP 3 Genuine Original

Actually posting about the serial number on my Genuine XP on my blog posts can be money without capital, since the longer blogspot google comes months if the bloggers said hehehe, so exhausted all of my blog, and recently added another that deleted my blog: (, luckily a week after didelete can still be seen through Cachenya blog, so there's still no copas sempet data data that are important to my own but hehehe, including genuine ini.serial XP serial number that has been the first reinstall I used every computer, even with the installation CD that already asphalt aka plasu original but, due to burning do not know how many times already in just this hehehe.SN XPnya instalan which I will share in all that you need, after I had already posted about How to download MP3 songs on 4shared.

Okay dah straight out, I try to share SN XP that can be used for all types of XP, Professional or other

1. V2C47 - MK7JD - 3R89F - D2KXW - VPK3J
2. H689T - BFM2F - R6GF8 - 9WPYM - B6378
3. WCBG6 - 48 773 - B4BYX - 73KJP - KM3K3

Now with three keys on windows xp you can like Original, which I normally use XP serial serial pertama.Untuk besides the above please try the following series:

XP 64-Bit: M4676 - 2VW7F - 6BCVH - 9QPBF - QBRBM

And if you use other OS than XP, for example vista, not hurt to try this series if you do not have the serial.

368Y7 - 49YMQ - VRCTY - 3V3RH - WRMG7
72PFD - BCBK8 - R7X4H - 6F2XJ - VVMP9

Windows Vista Business: J9QVT-JJMB9-RVJ38-M8KT6-DMT9M

Windows Vista Home Basic: KJTCW-YQGRK-XPQMR-YTQG8-DKVG6

Windows Vista Home Basic N: YQWWH-2YD6Y-V3K2X-H4H8V-WJ8WT

Windows Vista Home Premium: PYYBC-K9XT9-V92KD-6CT89-4VB82

Windows Vista Ultimate:

Windows Vista Ultimate RTM Build 6.0.6000.16384:

Windows Vista Enterprise: CYD8T-QHBMC-6RCMK-4GHRD-CRRB7

Black XP edition: W9VCJ-74DXW-JDDBV-PW777-WXD2T

Windows 7 (Seven) 32-Bit: 4HJRK-X6Q28-HWRFY-WDYHJ-K8HDH

Windows 7 64-Bit: JYDV8-H8VXG-74RPT-6BJPB-X42V4

Saturday, August 7, 2010

Java Fundamentals

The Java programming language has includes five simple arithmetic operators like are + (addition), - (subtraction), * (multiplication), / (division), and % (modulo). The following table summarizes them:

1. Source file's elements (in order)

  • Package declaration
  • Import statements
  • Class definitions

2. Importing packages doesn't recursively import sub-packages.

3. Sub-packages are really different packages, happen to live within an enclosing package. Classes in sub-packages cannot access classes in enclosing package with default access.

4. Comments can appear anywhere. Can't be nested. No matter what type of comments.

5. At most one public class definition per file. This class name should match the file name. If there are more than one public class definitions, compiler will accept the class with the file's name and give an error at the line where the other class is defined.

6. It's not required having a public class definition in a file. Strange, but true. J In this case, the file's name should be different from the names of classes and interfaces (not public obviously).

7. Even an empty file is a valid source file.

8. An identifier must begin with a letter, dollar sign ($) or underscore (_). Subsequent characters may be letters, $, _ or digits.

9. An identifier cannot have a name of a Java keyword. Embedded keywords are OK. true, false and null are literals (not keywords), but they can't be used as identifiers as well.

10. const and goto are reserved words, but not used.

11. Unicode characters can appear anywhere in the source code. The following code is valid.

ch\u0061r a = 'a';

char \u0062 = 'b';

char c = '\u0063';

12. Java has 8 primitive data types.

Data Type

Size (bits)

Initial Value

Min Value

Max Value









-128 (-27)

127 (27 - 1)





215 - 1




'\u0000' (0)

'\uFFFF' (216 - 1)





231 - 1





263 - 1











13. All numeric data types are signed. char is the only unsigned integral type.

14. Object reference variables are initialized to null.

15. Octal literals begin with zero. Hex literals begin with 0X or 0x.

16. Char literals are single quoted characters or unicode values (begin with \u).

17. A number is by default an int literal, a decimal number is by default a double literal.

18. 1E-5d is a valid double literal, E2d is not (since it starts with a letter, compiler thinks that it's an identifier)

19. Two types of variables.

a. Member variables

  • Accessible anywhere in the class.
  • Automatically initialized before invoking any constructor.
  • Static variables are initialized at class load time.
  • Can have the same name as the class.
b. Automatic variables method local
Must be initialized explicitly. (Or, compiler will catch it.) Object references can be initialized to null to make the compiler happy. The following code won't compile. Specify else part or initialize the local variable explicitly.

public String testMethod ( int a) {

String tmp;

if ( a > 0 ) tmp = "Positive";

return tmp;


· Can have the same name as a member variable, resolution is based on scope.

20. Arrays are Java objects. If you create an array of 5 Strings, there will be 6 objects created.

21. Arrays should be
  • Declared. (int[] a; String b[]; Object []c; Size should not be specified now)
  • Allocated (constructed). ( a = new int[10]; c = new String[arraysize] )
  • Initialized. for (int i = 0; i <>

22. The above three can be done in one step.

int a[] = { 1, 2, 3 }; (or )

int a[] = new int[] { 1, 2, 3 }; But never specify the size with the new statement.

23. Java arrays are static arrays. Size has to be specified at compile time. Array.length returns array's size. (Use Vectors for dynamic purposes).

24. Array size is never specified with the reference variable, it is always maintained with the array object. It is maintained in array.length, which is a final instance variable.

25. Anonymous arrays can be created and used like this: new int[] {1,2,3} or new int[10]

26. Arrays with zero elements can be created. args array to the main method will be a zero element array if no command parameters are specified. In this case args.length is 0.

27. Comma after the last initializer in array declaration is ignored.

int[] i = new int[2] { 5, 10}; // Wrong

int i[5] = { 1, 2, 3, 4, 5}; // Wrong

int[] i[] = {{}, new int[] {} }; // Correct

int i[][] = { {1,2}, new int[2] }; // Correct

int i[] = { 1, 2, 3, 4, } ; // Correct

28. Array indexes start with 0. Index is an int data type.

29. Square brackets can come after datatype or before/after variable name. White spaces are fine. Compiler just ignores them.

30. Arrays declared even as member variables also need to be allocated memory explicitly.

static int a[];

static int b[] = {1,2,3};

public static void main(String s[]) {

System.out.println(a[0]); // Throws a null pointer exception

System.out.println(b[0]); // This code runs fine

System.out.println(a); // Prints 'null'

System.out.println(b); // Prints a string which is returned by toString


31. Once declared and allocated (even for local arrays inside methods), array elements are automatically initialized to the default values.

32. If only declared (not constructed), member array variables default to null, but local array variables will not default to null.

33. Java doesn't support multidimensional arrays formally, but it supports arrays of arrays. From the specification - "The number of bracket pairs indicates the depth of array nesting." So this can perform as a multidimensional array. (no limit to levels of array nesting)

34. In order to be run by JVM, a class should have a main method with the following signature.

public static void main(String args[])

static public void main(String[] s)

35. args array's name is not important. args[0] is the first argument. args.length gives no. of arguments.

36. main method can be overloaded.

37. main method can be final.

38. A class with a different main signature or w/o main method will compile. But throws a runtime error.

39. A class without a main method can be run by JVM, if its ancestor class has a main method. (main is just a method and is inherited)

40. Primitives are passed by value.

41. Objects (references) are passed by reference. The object reference itself is passed by value. So, it can't be changed. But, the object can be changed via the reference.

42. Garbage collection is a mechanism for reclaiming memory from objects that are no longer in use, and making the memory available for new objects.

43. An object being no longer in use means that it can't be referenced by any 'active' part of the program.

44. Garbage collection runs in a low priority thread. It may kick in when memory is too low. No guarantee.

45. It's not possible to force garbage collection. Invoking System.gc may start garbage collection process.

46. The automatic garbage collection scheme guarantees that a reference to an object is always valid while the object is in use, i.e. the object will not be deleted leaving the reference "dangling".

47. There are no guarantees that the objects no longer in use will be garbage collected and their finalizers executed at all. gc might not even be run if the program execution does not warrant it. Thus any memory allocated during program execution might remain allocated after program termination, unless reclaimed by the OS or by other means.

48. There are also no guarantees on the order in which the objects will be garbage collected or on the order in which the finalizers are called. Therefore, the program should not make any decisions based on these assumptions.

49. An object is only eligible for garbage collection, if the only references to the object are from other objects that are also eligible for garbage collection. That is, an object can become eligible for garbage collection even if there are references pointing to the object, as long as the objects with the references are also eligible for garbage collection.

50. Circular references do not prevent objects from being garbage collected.

51. We can set the reference variables to null, hinting the gc to garbage collect the objects referred by the variables. Even if we do that, the object may not be gc-ed if it's attached to a listener. (Typical in case of AWT components) Remember to remove the listener first.

52. All objects have a finalize method. It is inherited from the Object class.

53. finalize method is used to release system resources other than memory. (such as file handles and network connections) The order in which finalize methods are called may not reflect the order in which objects are created. Don't rely on it. This is the signature of the finalize method.

protected void finalize() throws Throwable { }

In the descendents this method can be protected or public. Descendents can restrict the exception list that can be thrown by this method.

54. finalize is called only once for an object. If any exception is thrown in finalize, the object is still eligible for garbage collection (at the discretion of gc)

55. gc keeps track of unreachable objects and garbage-collects them, but an unreachable object can become reachable again by letting know other objects of its existence from its finalize method (when called by gc). This 'resurrection' can be done only once, since finalize is called only one for an object.

56. finalize can be called explicitly, but it does not garbage collect the object.

57. finalize can be overloaded, but only the method with original finalize signature will be called by gc.

58. finalize is not implicitly chained. A finalize method in sub-class should call finalize in super class explicitly as its last action for proper functioning. But compiler doesn't enforce this check.

59. System.runFinalization can be used to run the finalizers (which have not been executed before) for the objects eligible for garbage collection.

Sunday, August 1, 2010

Please Read Them Carefully and Forward to all of Your Friends - Health is Wealth

Hey Friends I am sharing with you some true Facts .. Please Follow them and forward to your Friends if they use them....

Don't put your mobile closer to your ears until the
recipient answers, Because directly after dialing, the mobile
phone would use it's maximum signaling power,
which is: 2watts = 33dbi. Please Be Careful. Please use left ear while using
cell (mobile), because if you use the right one it may affect brain directly. This is a true fact from Apollo medical team.

Do not drink APPY FIZZ . It contains cancer causing agent.

3) Mentos
Don't eat Mentos before or after drinking Coke or
Pepsi coz the
person will die immediately as the mixture
becomes cyanide. Please fwd to whom u care.

4) Kurkure
Don't eat kurkure because it contains high amount of
plastic if U don't Believe burn kurkure n u can see
plastic melting. Please forward to all!!!!!!!!! !! News
report from
Times of India

5) Avoid these tablets as they are very dangerous
* D cold
* Vicks action- 500
* Actified
* Coldarin
* Co some
* Nice
* Nimulid
* Cetrizet-D
They contain Phenyl- Propanol -Amide PPA.Which Causes strokes, and these tablets are banned in U.S.

6) Cotton Ear Buds
Cotton Ear Buds... (Must read it) Please do not show sympathy to people selling buds on roadside or at Signals..... Just wanted to warn you people not to buy those packs of ear buds you get at the roadside. It's made from cotton that has already been used in hospitals. They take all the dirty, blood and pus filled cotton, wash it, bleach it and use it to make ear buds. So, unless you want
to become the first person in the world to get Herpes Zoster Oticus (a viral infection of the inner, middle, and external ear) of the ear and that too from a cotton bud, DON'T BUY THEM! Please forward to all this may be
helpful for someone..... .......

Please forward to all your near and dear ones....!