While Java is one of the most in-demand and widely used programming languages in the world, it is not without its detractors. Java is not a particularly beginner-friendly language and it is rife with ...

at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225) at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266 ...

网上也有相关的提问：回答的一般是，控制指针错误，控制操作，有个空指针什么的，本人不太明白，请高手给点详细的提示。

It doesn’t take much Java development experience to learn firsthand what the NullPointerException is about. In fact, one person has highlighted dealing with this as the number one mistake Java ...