我正在运行一个带openjdk-8-jdk-armhf
的无头linux盒子,当我运行我的应用程序时,该行
METRICS = new JPanel().getFontMetrics(FONT);
抛出NullPointerException,返回RepaintManager.currentManager(RepaintManager.java:262)
,如下所示:
public static RepaintManager currentManager(Component c) {
// Note: DisplayChangedRunnable passes in null as the component, so if
// component is ever used to determine the current
// RepaintManager, DisplayChangedRunnable will need to be modified
// accordingly.
return currentManager(AppContext.getAppContext());
}
完整跟踪如下:
java.lang.NullPointerException
at javax.swing.RepaintManager.currentManager(RepaintManager.java:262)
at javax.swing.JComponent.repaint(JComponent.java:4799)
at java.awt.Component.repaint(Component.java:3303)
at javax.swing.JComponent.setFont(JComponent.java:2756)
at javax.swing.LookAndFeel.installColorsAndFont(LookAndFeel.java:208)
at javax.swing.plaf.basic.BasicPanelUI.installDefaults(BasicPanelUI.java:66)
at javax.swing.plaf.basic.BasicPanelUI.installUI(BasicPanelUI.java:56)
at javax.swing.JComponent.setUI(JComponent.java:664)
at javax.swing.JPanel.setUI(JPanel.java:153)
at javax.swing.JPanel.updateUI(JPanel.java:126)
at javax.swing.JPanel.<init>(JPanel.java:86)
at javax.swing.JPanel.<init>(JPanel.java:109)
at javax.swing.JPanel.<init>(JPanel.java:117)
at lukemoll.MyClass.<init>(MyClass.java:15)
我可以通过jsvc
和java
命令重现此错误。
答案 0 :(得分:0)
这个(
Canvas
)也可以在无头模式下工作。
我最终使用new Canvas().getFontMetrics(font);
,我不知道上次我是如何让它工作的,但这可以在我的机器上工作(tm)。