JList.getPreferredScrollableViewportSize() has the following syntax.
public Dimension getPreferredScrollableViewportSize()
In the following code shows how to use JList.getPreferredScrollableViewportSize() method.
import java.awt.BorderLayout; import java.awt.Dimension; /*from w ww . j av a2 s . c om*/ import javax.swing.JFrame; import javax.swing.JList; import javax.swing.JScrollPane; public class Main { public static void main(final String args[]) { String labels[] = { "A", "B", "C", "D", "E" }; JFrame frame = new JFrame("Sizing Samples"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JList jlist1 = new JList(); jlist1.setListData(labels); jlist1.setVisibleRowCount(4); JScrollPane scrollPane1 = new JScrollPane(jlist1); frame.add(scrollPane1, BorderLayout.NORTH); Dimension m = jlist1.getPreferredScrollableViewportSize(); frame.setSize(300, 350); frame.setVisible(true); } }