Java JTabbedPane问题

Question

frame采用Borderlayout，JTabbedPane放在中间是横向的，放在东面就变成纵向的，增加了东面的大小也没有用。
JTabbedPane tab = new JTabbedPane(JTabbedPane.TOP);
tab.addTab("1", new JPanel());
tab.addTab("2", new JPanel());
JTabbedPane tab2 = new JTabbedPane(JTabbedPane.TOP);
tab2.addTab("1", new JPanel());
tab2.addTab("2", new JPanel());
listPanel.setPreferredSize(new Dimension(500, 400));
listPanel.add(tab,BorderLayout.CENTER);
this.add(tab2,BorderLayout.CENTER);
this.add(listPanel,BorderLayout.EAST);

Answer 1

https://zhidao.baidu.com/question/454899207756969845.html