try this..
add two jlabel on drug list jframe..
1)itemIDlbl
2)itemNamelbl
then..
Note: DT is jtable variable name.
DT.getSelectionModel().addListSelectionListener(new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent e) {
               itemIDlbl.setText(DT.getValueAt(DT.getSelectedRow(), 0).toString());
                 itemNamelbl.setText(DT.getValueAt(DT.getSelectedRow(), 1).toString());
            }
        });
now you have stored selected row items in jlabel. now you can simple pass it to edit inventory..
private void selectActionPerformed(java.awt.event.ActionEvent evt) {                                         
       String id=itemIDlbl.getText();
       String name=itemNamelbl.getText();
        EditInventory ei =new EditInventory();
    ei.get(id,name);
    this.dispose();
    ei.setVisible(true);
    }           
make a method in edit inventory to accept values..
 public void get (String id,String name)
    {
        id_txt.setText(id);
        name_txt.setText(name);
    }