Debian Jessie: installing OpenJDK-8, Mysql JDBC and PostgreSQL JDBC

Install all packages:
# apt-get install openjdk-8-jdk libmysql-java libpostgresql-jdbc-java libpostgresql-jdbc-java-doc
Note: openjdk-8-jdk requires backports repository, add this into /etc/apt/sources.list
deb http://ftp.de.debian.org/debian jessie-backports main
To set Java Environment for all users, add/edit /etc/environment:
JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64"
CLASSPATH=".:/usr/share/java/mysql.jar:/usr/share/java/postgresql-jdbc4.jar"
Note: if you prefered to use postgresql-jdbc3, replace /usr/share/java/postgresql-jdbc4.jar with /usr/share/java/postgresql.jar
Example Java code loading MySQL:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
class TestDB {
    /*
      /usr/share/java
      http://dev.mysql.com/doc/connector-j/5.1/en/
      https://jdbc.postgresql.org/documentation/documentation.html
    */
   static Connection conn = null;   
   public static void main(String[] args) {
      // MySQL
      try {
         System.out.println("Loading Class com.mysql.jdbc.Driver");
         Class.forName("com.mysql.jdbc.Driver") ;
         System.out.println("Loading com.mysql.jdbc.Driver Successful");
         conn = DriverManager.getConnection("jdbc:mysql://localhost/database?user=user&password=password");
         // Do something with the Connection
         System.out.println("Test Connection Successful");
      } catch (SQLException ex) {
         // handle any errors
         System.out.println("SQLException: " + ex.getMessage());
         System.out.println("SQLState: " + ex.getSQLState());
         System.out.println("VendorError: " + ex.getErrorCode());
      } catch (ClassNotFoundException ex) {
         System.out.println("Class Not Found: " + ex.getMessage());
      }
      // PostgreSQL
      try {
         System.out.println("Loading Class org.postgresql.Driver");
         Class.forName("org.postgresql.Driver");
         System.out.println("Loading org.postgresql.Driver Successful");
         String url = "jdbc:postgresql://localhost/database";
         Properties props = new Properties();
         props.setProperty("user","user");
         props.setProperty("password","password");
         props.setProperty("ssl","true");
         conn = DriverManager.getConnection(url, props); 
         // or
         url = "jdbc:postgresql://localhost/database?user=user&password=password&ssl=true";
         Connection conn = DriverManager.getConnection(url);
         // Do something with the Connection
         System.out.println("Test Connection Successful");
      } catch (SQLException ex) {
         // handle any errors
         System.out.println("SQLException: " + ex.getMessage());
         System.out.println("SQLState: " + ex.getSQLState());
         System.out.println("VendorError: " + ex.getErrorCode());
      } catch (ClassNotFoundException ex) {
         System.out.println("Class Not Found: " + ex.getMessage());
      }
   }
}
References: