java-jdbc: How to find the information about a database by java code?

DatabaseMetaData interface provides methods to get meta data of a database such as database product name, database product version, driver name, name of total number of tables, name of total number of views etc.

Commonly used methods of DatabaseMetaData interface :
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• public String getDriverName()throws SQLException: it returns the name of the JDBC driver.
• public String getDriverVersion()throws SQLException: it returns the version number of the JDBC driver.
• public String getUserName()throws SQLException: it returns the username of the database.
• public String getDatabaseProductName()throws SQLException: it returns the product name of the database.
• public String getDatabaseProductVersion()throws SQLException: it returns the product version of the database.
• public ResultSet getTables(String catalog, String schemaPattern, String tableNamePattern, String[] types)throws SQLException: it returns the description of the tables of the specified catalog. The table type can be TABLE, VIEW, ALIAS, SYSTEM TABLE, SYNONYM etc.

How to get the object of DatabaseMetaData:
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The getMetaData() method of Connection interface returns the object of DatabaseMetaData.
Syntax:
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public DatabaseMetaData getMetaData()throws SQLException

********************** Simple Example of DatabaseMetaData interface **********************

import java.sql.*;
class Dbmd{
public static void main(String args[]){
try{
Class.forName("oracle.jdbc.driver.OracleDriver");

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

DatabaseMetaData dbmd=con.getMetaData();

System.out.println("Driver Name: "+dbmd.getDriverName());
System.out.println("Driver Version: "+dbmd.getDriverVersion());
System.out.println("UserName: "+dbmd.getUserName());
System.out.println("Database Product Name: "+dbmd.getDatabaseProductName());
System.out.println("Database Product Version: "+dbmd.getDatabaseProductVersion());

con.close();

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

}
}
================================ Output ==================================
Driver Name: Oracle JDBC Driver
Driver Version: 10.2.0.1.0XE
Database Product Name: Oracle
Database Product Version: Oracle Database 10g Express Edition
Release 10.2.0.1.0 -Production

*********** Example of DatabaseMetaData interface that prints total number of tables ***********

import java.sql.*;
class Dbmd2{
public static void main(String args[]){
try{
Class.forName("oracle.jdbc.driver.OracleDriver");

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

DatabaseMetaData dbmd=con.getMetaData();
String table[]={"TABLE"};
ResultSet rs=dbmd.getTables(null,null,null,table);

while(rs.next()){
System.out.println(rs.getString(3));
}

con.close();

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

}
}
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*********** Example of DatabaseMetaData interface that prints total number of views ***********

import java.sql.*;
class Dbmd3{
public static void main(String args[]){
try{
Class.forName("oracle.jdbc.driver.OracleDriver");

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

DatabaseMetaData dbmd=con.getMetaData();
String table[]={"VIEW"};
ResultSet rs=dbmd.getTables(null,null,null,table);

while(rs.next()){
System.out.println(rs.getString(3));
}

con.close();

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

}
}