By default, a table component allows multiple selections. To control the selection behavior, see e939 Enabling Row, Column, or Cell Selections in a JTable Component. 
    JTable table = new JTable();
    
    // Get default selection mode
    int selMode = table.getSelectionModel().getSelectionMode();
    // MULTIPLE_INTERVAL_SELECTION
    
    // Allow only single a selection
    table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    
    // Allow selection to span one contiguous set of rows,
    // visible columns, or block of cells
    table.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
    
    // Allow multiple selections of rows, visible columns, or cell blocks (default)
    table.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);