Can main() method overloaded ??

Yes, main() can be overloaded. Let’s see the following examples for better clarity :

ExampleMain.java

class ExampleMain

{

public static void main(String[] args)

{

System.out.println("Hiii");

}

public static void main(int x)

{

System.out.println("Hello");

}

}

Output

Hiii

JAVA 9 private method in interface

Hii frnds, here we will know an exciting feature of JAVA 9, that is definition of private method in interface. That means it is possible that we can happily define a private method inside the interface.

IntefaceExample.java

interface Test

{

void show();

default void print()

{

System.out.println("JAVA means SILAN TECHNOLOGY");

display();

}

private void display()

{

System.out.println("www.java8s.com");

}

}

class Demo implements Test

{

public void show()

{

System.out.println("SILAN TECHNOLOGY");

}

}

class InterfaceExample

{

public static void main(String[] args)

{

Demo obj=new Demo();

obj.show();

obj.print();

}

} 

Output

 SILAN TECHNOLOGY

JAVA means SILAN TECHNOLOGY

www.java8s.com

Can we compile and execute a java program without a class??

Ans: Yes, we can compile and execute without a class. Let’s see the following code:

Test43.java

enum Test43{

;  

public static void main(String[] args)

{

System.out.println("Silan Technology");

}

}

Output

Silan Technology

JAVA 9 Features

JAVA 9 Features :

1. Modularity -- jigsaw

2. REPL --  JShell

3. try with resource enhancements

4. Factory methods in collection

5. private methods in interface

6. Stream API enhancements

7. Http 2 Client(java.util.http)

8. G1 garbage collector

JDBC Program - How to Create a table

JdbcExample1.java

package java8s;

import java.sql.*;

public class JdbcExample1 {

     public static void main(String[] args) throws Exception{

         

          Class.forName("oracle.jdbc.driver.OracleDriver");

         

          Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","system","oracle");

         

          Statement st=con.createStatement();

         

          String s= "create table customer("

                   + "C_ID NUMBER(5) NOT NULL, "

                   + "CNAME VARCHAR(100) NOT NULL, "

                   + "Caddress VARCHAR(200) NOT NULL, "

                   + "Creport_DATE DATE NOT NULL, " + "PRIMARY KEY (C_ID) "

                   + ")";

         

          System.out.println(s);

          st.execute(s);

          System.out.println("table is created");

         

     }

}

Output

create table customer1(C_ID NUMBER(5) NOT NULL, C_NAME VARCHAR(20) NOT NULL, C_add VARCHAR(20) NOT NULL, C_DATE DATE NOT NULL, PRIMARY KEY (C_ID) )

table is created

JAVA Program to generate OTP

Otp.java

package java8s;

import java.util.Random;

public class Otp {

     static char[] sendOtp(int length){

          System.out.println("your otp for this transaction is:");

          String numbers="0123456789";

          Random r=new Random();

          char[] otp=new char[length];

         

          for(int i=0;i<length;i++)

          {

              otp[i]=numbers.charAt(r.nextInt(numbers.length()));

          }

          return otp;

     }

    

    

     public static void main(String[] args) {

         

          System.out.println("generating otp....");

          System.out.println(sendOtp(4));

     }

}

Output 

generating otp....

your otp for this transaction is:

7176

How we can sort primitive types or Object array and list with a simple JAVA program ?

package com.java8s.sort;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

public class JavaObjectSortingExample {

    /**

     * This class shows how to sort primitive arrays,

     * Wrapper classes Object Arrays

     * @param args

     */

    public static void main(String[] args) {

        //sort primitives array like int array

        int[] ar = {50,100,40,30};

        Arrays.sort(ar);

        System.out.println(Arrays.toString(ar));

       

        //sorting String array

        String[] arr = {"A", "C", "B", "Z", "E"};

        Arrays.sort(arr);

        System.out.println(Arrays.toString(arr));

       

        //sorting list of objects of Wrapper classes

        List<String> l = new ArrayList<String>();

        l.add("A");

        l.add("C");

        l.add("B");

        l.add("Z");

        l.add("E");

        Collections.sort(l);

        for(String str: l) System.out.print(" "+str);

    }

}

Output

 [30,40,50,100]

 [A,B,C,E,Z]

  A B C E Z