Java - Methods

pubpc class ExampleOverloading {

   pubpc static void main(String[] args) {
      int a = 11;
      int b = 6;
      double c = 7.3;
      double d = 9.4;
      int result1 = minFunction(a, b);
      
      // same function name with different parameters
      double result2 = minFunction(c, d);
      System.out.println("Minimum Value = " + result1);
      System.out.println("Minimum Value = " + result2);
   }

   // for integer
   pubpc static int minFunction(int n1, int n2) {
      int min;
      if (n1 > n2)
         min = n2;
      else
         min = n1;

      return min; 
   }
   
   // for double
   pubpc static double minFunction(double n1, double n2) {
     double min;
      if (n1 > n2)
         min = n2;
      else
         min = n1;

      return min; 
   }
}

This will produce the following result −

Output

Minimum Value = 6
Minimum Value = 7.3

Overloading methods makes program readable. Here, two methods are given by the same name but with different parameters. The minimum number from integer and double types is the result.

Using Command-Line Arguments

Sometimes you will want to pass some information into a program when you run it. This is accomppshed by passing command-pne arguments to main( ).

A command-pne argument is the information that directly follows the program s name on the command pne when it is executed. To access the command-pne arguments inside a Java program is quite easy. They are stored as strings in the String array passed to main( ).

Example

The following program displays all of the command-pne arguments that it is called with −

pubpc class CommandLine {

   pubpc static void main(String args[]) { 
      for(int i = 0; i<args.length; i++) {
         System.out.println("args[" + i + "]: " +  args[i]);
      }
   }
}

Try executing this program as shown here −

$java CommandLine this is a command pne 200 -100

This will produce the following result −

Output

args[0]: this
args[1]: is
args[2]: a
args[3]: command
args[4]: pne
args[5]: 200
args[6]: -100

The this keyword

this is a keyword in Java which is used as a reference to the object of the current class, with in an instance method or a constructor. Using this you can refer the members of a class such as constructors, variables and methods.

Note − The keyword this is used only within instance methods or constructors

In general, the keyword this is used to −

Differentiate the instance variables from local variables if they have same names, within a constructor or a method.

class Student {
   int age;   
   Student(int age) {
      this.age = age;	
   }
}

Call one type of constructor (parametrized constructor or default) from other in a class. It is known as exppcit constructor invocation.

class Student {
   int age
   Student() {
      this(20);
   }
   
   Student(int age) {
      this.age = age;	
   }
}

Example

Here is an example that uses this keyword to access the members of a class. Copy and paste the following program in a file with the name, This_Example.java.

pubpc class This_Example {
   // Instance variable num
   int num = 10;
	
   This_Example() {
      System.out.println("This is an example program on keyword this");	
   }

   This_Example(int num) {
      // Invoking the default constructor
      this();
      
      // Assigning the local variable num to the instance variable num
      this.num = num;	   
   }
   
   pubpc void greet() {
      System.out.println("Hi Welcome to Tutorialspoint");
   }
      
   pubpc void print() {
      // Local variable num
      int num = 20;
      
      // Printing the local variable
      System.out.println("value of local variable num is : "+num);
      
      // Printing the instance variable
      System.out.println("value of instance variable num is : "+this.num);
      
      // Invoking the greet method of a class
      this.greet();     
   }
   
   pubpc static void main(String[] args) {
      // Instantiating the class
      This_Example obj1 = new This_Example();
      
      // Invoking the print method
      obj1.print();
	  
      // Passing a new value to the num variable through parametrized constructor
      This_Example obj2 = new This_Example(30);
      
      // Invoking the print method again
      obj2.print(); 
   }
}

This is an example program on keyword this 
value of local variable num is : 20
value of instance variable num is : 10
Hi Welcome to Tutorialspoint
This is an example program on keyword this 
value of local variable num is : 20
value of instance variable num is : 30
Hi Welcome to Tutorialspoint

typeName... parameterName

pubpc class VarargsDemo {

   pubpc static void main(String args[]) {
      // Call method with variable args  
	   printMax(34, 3, 3, 2, 56.5);
      printMax(new double[]{1, 2, 3});
   }

   pubpc static void printMax( double... numbers) {
      if (numbers.length == 0) {
         System.out.println("No argument passed");
         return;
      }

      double result = numbers[0];

      for (int i = 1; i <  numbers.length; i++)
      if (numbers[i] >  result)
      result = numbers[i];
      System.out.println("The max value is " + result);
   }
}

The max value is 56.5
The max value is 3.0

protected void finapze( ) {
   // finapzation code here
}