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  1. N ART ADAR SARASAWATHI COLLEGE OF ART &SCIENCE,Theni
  2. METHODS AND CLASSES  It examies several topics relating to methods,including overloading,parameter,passing and recrsion.  The class , discussing access control , the use of the keyword staic , and or of java’s most important built-in classes string.
  3. Overloading methods  When this is the case the methods are said to be overloading and the process is referred to as method overloading.  Thus overloaded methods must may have different return/or number of their parameters.  two versions of a method : Overloaded method Simply executes method
  4.  As you can see test() is overloaded four times.  at no parameters,  The first version takes no parameters,  The second takes integer parameter,s  Third tat the takes two integer parameters,  Fourth takes one double parameter.  The fact that the fourth of test() also return a value is of no consequence relative to overloaded.  Since return types do not play a role in overload resolution.
  5. Using objects as parameters  As you can , see the equal() method inside Test compares two objects for equality and return the result.  If they contain the same values, that then the method return true.  Otherwise it return false. Notice that the parameter o in equals() Test as its type.  Version of Box allows one object to initialize.
  6. A closer look at argument passing  There are two way is that a language.  The first way is call-by-value.  Value of argument into the formal parameter of the subroutine.  The second way an argument can be passed is call- by-reference.  Not value of the argument.  Operation that occur inside meth() have no effect on the values of a and b used in the call;
  7. Returning objects  A method can return any type of data including class type that you create.  incrByTen() meyhod.  As you each time incrByTen() is invoked new object is created and a reference to is returned to the calling routine.  The all object are dynamically allocated using new, you don’t need to worry about an object going out-of- scope.
  8. recursion  Java support recursion.  A method that calls itself is said to be recursive.  The classic example recursion product of all the whole numbers between 1 and N of the factorial of number.  for example 3 factorial 1*2*3, or 6.  Use println() statements liberally during development .
  9. Introducing Access Control  As you know encapsulation link data with the code that manipulates.  Encapsulation provide another another important attritube: access control.  Correctly implemented a class create a “black box inner working not open to tempering.  For example consider the stack class end of true the methods push() and pop()provide a controlled interface to the stack not enforced.  Java’s access speccifiers are public,private,protected.  Protected applies only when inheritance.
  10.  Let’s begin by defining public and private. when a member of a class is modified a the public specified then the member can be accessed by any other code.  Public methods:  setc() and get().  Remove the comment symbol from the beginning of the.  ob.c=100;
  11. Understanding static  There will be times when you will want to define a class member that will be used independently of any object of that class.  When a member is decleared static it can be accessed before any objects of class are created.  Example : static main() decleared as static called before any objects exist.  Methods declared as static methods:  They can only call other static methods.  They must only access static data.  They cannot refer to this or super in any way.
  12.  static method from outside its class, classname.method() • Inside main(),the static method callme() and static variable b are accessed through class name staticDemo.
  13. Introducing final  A variable can be declared as final.  Subsequent parts of your program can now use FILE_OPEN,etc., as if they were constants,without fear that a value has been changed.  Thus final variable is essentially a constant.  This second usage of final is described in the next inheritance is described.
  14. Array revisited  Now that you know about classes, an important point can about about arrays:  The size of an array-that is the number of element that an array can hold-is found in its length instance variable.  Program create two stacks:  one five elements other eight element deep.  array maintain their own length own information makes easy create stacks of any size.
  15.  Inner class named Inner within scope of class Outer.  Inner can directly access the variable outer_x.  The main() method of InnerClassDemo creates an instance of class outer and invokes its test() method.  Instance variable of showy().
  16. Introducing nested and inner meth classes  Such classes are known as nested classes.  There are two type of nested classess:  static and non-static.  The most important type of static nested classes inner class.  The class named outer has one instance variable named outer_x, one instance method named test() and defines inner called inner.  Inner class named Inner is defined scope class Outer.
  17. Exploring the string class  String is probably the most commonly used in java’s class library. • Even string constants are actually string objects. • If you need to change a string can always create a new one that contains the modifications. • Java defines a peer class String called StringBufffer, • “I like Java”.
  18. Using command-line arguments  This is accompolihed passing command-line arguments to main().  A command –line argument is the information that directly follow the program’s name on the command line when is executed.  The first command line argument is stored at args[0]  The second a args[1]
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