JDBC
//STEP 1. Import required packagesimport java.sql.*;
public class FirstExample {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/EMP";

   //  Database credentials
   static final String USER = "username";
   static final String PASS = "password";

   public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   try{
      //STEP 2: Register JDBC driver
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to database...");
      conn = DriverManager.getConnection(DB_URL,USER,PASS);

      //STEP 4: Execute a query
      System.out.println("Creating statement...");
      stmt = conn.createStatement();
      String sql;
      sql = "SELECT id, first, last, age FROM Employees";
      ResultSet rs = stmt.executeQuery(sql);

      //STEP 5: Extract data from result set
      while(rs.next()){
         //Retrieve by column name
         int id  = rs.getInt("id");
         int age = rs.getInt("age");
         String first = rs.getString("first");
         String last = rs.getString("last");

         //Display values
         System.out.print("ID: " + id);
         System.out.print(", Age: " + age);
         System.out.print(", First: " + first);
         System.out.println(", Last: " + last);
      }
      //STEP 6: Clean-up environment
      rs.close();
      stmt.close();
      conn.close();
   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            stmt.close();
      }catch(SQLException se2){
      }// nothing we can do
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");}//end main}//end FirstExample


THREAD
//16BCI0117 GOKULA KRISHNAN S
class Poll {
static private int a , b , c;
//Synchronized method if vote for A
static synchronized public void voteA () {
a++;
}
//Synchronized method if vote for B
static synchronized public void voteB () {
b++;
}
//Synchronized method if vote for C
static synchronized public void voteC () {
c++;
}
//Getter Methods
static public int getA () {
return a;
}
static public int getB () {
return b;
}
static public int getC () {
return c;
}
}
class VoteCount {
//Switch case statements to cast votes
private static void voteCandidate ( char ch ) {
switch (ch) {
case 'A' :
Poll.voteA();
break ;
case 'B' :
Poll.voteB();
break ;
case 'C' :
Poll.voteC();
break ;
}
}
public static void main ( String [] args ) throws InterruptedException {
int strength = 240 ;
char votes[] = new char[strength];
char candidates[] = { 'A' , 'B' , 'C' };
// randomly vote candidates
for ( int i = 0; i < strength; i++) {
int ch = (int) (Math.random() * 3 );
char cand = candidates[ch];
votes[i] = cand;
}
int r1 = 0 , r2 = strength / 3 , r3 = strength / 3 * 2 ;
// create threads with anonymous class declaration
Thread t1 = new Thread() {
public void run () {
for ( int i = r1; i < r2; i++)
voteCandidate(votes[i]);
}
};
Thread t2 = new Thread() {
public void run () {
for ( int i = r2; i < r3; i++)
voteCandidate(votes[i]);
}
};
Thread t3 = new Thread() {
public void run () {
for ( int i = r3; i < strength; i++)
voteCandidate(votes[i]);
}
};
t1.start();
t2.start();
t3.start();
// join main thread
t1.join();
t2.join();
t3.join();
int a , b , c;
a = Poll.getA();
b = Poll.getB();
c = Poll.getC();
System.out.println( "voting results: " );
System.out.println( "A: " + a);
System.out.println( "B: " + b);
System.out.println( "C: " + c);
System.out.print( "Congrats " );
// get max vote candidate
if (a > b)
if (c > a)
System.out.print( "C " );
else
System.out.print( "A " );
else if (c > b)
System.out.print( "C " );
else
System.out.print( "B " );
}
}

FILE
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.io.*;
import java.util.*;

class File {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
try {
FileOutputStream fout = new FileOutputStream("student.txt");
ObjectOutputStream obout = new ObjectOutputStream(fout);
for (int i = 0; i < 2; i++) {
String name = scan.nextLine();
String id = scan.nextLine();
Student student = new Student(name, id);
obout.writeObject(student);

}
obout.close();
fout.close();
} catch (Exception e) {
System.out.println(e);
}

try {
FileInputStream fin = new FileInputStream("student.txt");
ObjectInputStream oin = new ObjectInputStream(fin);
Student obj;
while (oin.available() != -1) {
obj = (Student) oin.readObject();
System.out.println(obj);
}
oin.close();
fin.close();
} catch (Exception e) {
System.out.println(e);
}

}
}

class Student implements Serializable {
String name, id;

public Student() {
}

public Student(String name, String id) {
this.name = name;
this.id = id;
}

public String getName() {
return this.name;
}

public void setName(String name) {
this.name = name;
}

public String getId() {
return this.id;
}

public void setId(String id) {
this.id = id;
}

public Student name(String name) {
this.name = name;
return this;
}

public Student id(String id) {
this.id = id;
return this;
}

public String toString() {
return "{" + " name='" + getName() + "'" + ", id='" + getId() + "'" + "}";
}

}