Access to postgresql server from Spring application - spring

Question

I have a Spring application (Hibernate c3p0) that connects well to an Oracle DB server.
I want to do the same thing with a PostgreSQL DB server, but it sends me the error java.net.UnknownHostException.
In applicationContext, my dataSource is :
<bean id="appDS" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="org.postgresql.Driver" />
<property name="jdbcUrl" value="jdbc:postgresql://THE_SERVER:5432/schema" />
<property name="user" value="appc0" />
<property name="password" value="THE_PWD" />
</bean>
I tried a connection from another very simple java application (from the same server):
public static void main(String[] args) {
try {
System.out.println("TEST Driver Manager START");
Class.forName("org.postgresql.Driver");
String url = "jdbc:postgresql://THE_SERVER:5432/schema";
String user = "appc0";
String passwd = "THE_PWD";
Connection conn = DriverManager.getConnection(url, user, passwd);
System.out.println("Schema : " + conn.getSchema());
System.out.println("ClientInfo : " + conn.getClientInfo());
System.out.println("TEST Driver Manager END");
System.out.println("TEST C3P0 START");
ComboPooledDataSource cpds = new ComboPooledDataSource();
cpds.setDriverClass( "org.postgresql.Driver" );
cpds.setJdbcUrl( "jdbc:postgresql://THE_SERVER:5432/schema" );
cpds.setUser("appc0");
cpds.setPassword("THE_PWD");
System.out.println("User :"+ cpds.getUser());
System.out.println("TEST C3P0 END");
} catch(Exception e) {
e.printStackTrace();
}
And no mistake in this case, I connect well. This does not seem to be a network problem.
Does anyone know where the problem may come from?
Versions are:
postgresql-42.2.0.jre7.jar
c3p0-0.9.1.2.jar