void problemCode1(DataSource ds)
{
  Connection conn = ds.getConnection();
  PreparedStatement stmt = conn.prepareStatement("SELECT * FROM MY_TABLE");
  //...
  conn.close();
}
		
void problemCode2(DataSource ds)
{
  Connection conn = null;
  try
  {
    Connection conn = ds.getConnection();
    PreparedStatement stmt = conn.prepareStatement("SELECT * FROM MY_TABLE");
    //...
  }
  finally
  {
    conn.close();
  }
}

void problemCode3(DataSource ds)
{
  Connection conn = ds.getConnection();;
  try
  {
    //...
  }
  finally
  {
    
    conn.getAutoCommit(); // can throw an exeption and next line never execute
    conn.close();
    
  }
}

Connection conn = ds.getConnection();
try
{
  PreparedStatement stmt = conn.prepareStatement("SELECT * FROM MY_TABLE");
	//...
}
finally
{
  conn.close();
}