Statement.ececuteUpdate() closes ResultSet obtained from same Statement

I am not sure if this is a bug or a feature, but here it goes:

package cpssd.postgresql;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.sql.*;

public class TicketIT {
   private static Connection getConnection() throws SQLException {       return DriverManager.getConnection("jdbc:postgresql:postgres");   }
   @Before   public void createTable() throws SQLException {       try (Connection c = getConnection();            Statement s = c.createStatement()) {           s.executeUpdate("CREATE TABLE test(a INT)");       }   }
   @After   public void dropTable() throws SQLException {       try (Connection c = getConnection();            Statement s = c.createStatement()) {           s.executeUpdate("DROP TABLE test");       }   }
   @Test(expected = SQLException.class)   public void testSharedStatementClosesResultSet() throws SQLException {       try (Connection c = getConnection();            Statement s = c.createStatement()) {           try (ResultSet rs = s.executeQuery("SELECT a FROM test")) {               s.executeUpdate("INSERT INTO test(a) VALUES (1)");               // Expected false, but throws SQLException: This statement has been closed.               assert !rs.next();           }       }   }
   @Test   public void testUsingAnotherStatementWorks() throws SQLException {       try (Connection c = getConnection();            Statement s1 = c.createStatement()) {           try (ResultSet rs = s1.executeQuery("SELECT a FROM test")) {               try (Statement s2 = c.createStatement()) {                   s2.executeUpdate("INSERT INTO test(a) VALUES (1)");               }               assert !rs.next();           }       }   }
}