PSQLException "Could not open SSL root certificate file" when attempting SSL connection with Postgres via JDBC - postgresql

Question

In Java 15, using the PostgreSQL JDBC Driver (ver. 42.2.18, JDBC4.2) from jdbc.postgresql.org with this DataSource:
PGSimpleDataSource ds = new PGSimpleDataSource();
ds.setServerNames( new String[] { "my-server-address" } );
ds.setPortNumbers( new int[] { 25060 } );
ds.setSsl( true );
ds.setDatabaseName( "mydb" );
ds.setUser( "scott" );
ds.setPassword( "tiger" );
this.dataSource = ds;
…the code Connection conn = this.dataSource.getConnection(); throws this exception:
org.postgresql.util.PSQLException: Could not open SSL root certificate file /Users/basilbourque/.postgresql/root.crt.
I know my Postgres 12 server is set up for SSL connections, as my IntelliJ Ultimate has a database access feature (DataGrip) that is successfully connecting with SSL (TLS) protection.
So what is wrong my DataSource configuration in JDBC?

Answer 1

Thanks to this Github issue page for the pgjdbc driver, I found this post by davecramer:
As of 42.2.5 ssl=true implies verify-full as per the release notes. If you wish to get the old behaviour use sslmode=require
Sure enough, replacing ds.setSsl( true ); with ds.setSslMode( "require" ); allowed my JDBC driver make a connection via DataSource.
PGSimpleDataSource ds = new PGSimpleDataSource();
ds.setServerNames( new String[] { "my-server-address" } );
ds.setPortNumbers( new int[] { 25060 } );
ds.setSslMode( "require" ); // Replaces: ds.setSsl( true );
ds.setDatabaseName( "mydb" );
ds.setUser( "scott" );
ds.setPassword( "tiger" );
this.dataSource = ds;
I have no idea what any of these SSL/TLS related options are actually doing, but this worked for me to connect to my DigitalOcean managed Postgres database server.
The following code snippet now runs successfully:
try
(
Connection conn = this.dataSource.getConnection() ;
Statement stmt = conn.createStatement() ;
)
{
String sql =
"""
SELECT uuid_generate_v1()
;
""";
try (
ResultSet rs = stmt.executeQuery( sql ) ;
)
{
while ( rs.next() )
{
UUID uuid = rs.getObject( 1 , UUID.class );
System.out.println( "uuid = " + uuid );
}
}
}
catch ( SQLException e )
{
e.printStackTrace();
}