问题描述
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExceptionat Hello.BeatBox.buildTrackAndStart(BeatBox.java:92)at Hello.BeatBox$MyStartListener.actionPerformed(BeatBox.java:124)at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)at java.awt.Component.processMouseEvent(Component.java:6267)at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)at java.awt.Component.processEvent(Component.java:6032)at java.awt.Container.processEvent(Container.java:2041)at java.awt.Component.dispatchEventImpl(Component.java:4630)at java.awt.Container.dispatchEventImpl(Container.java:2099)at java.awt.Component.dispatchEvent(Component.java:4460)at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)at java.awt.Container.dispatchEventImpl(Container.java:2085)at java.awt.Window.dispatchEventImpl(Window.java:2478)at java.awt.Component.dispatchEvent(Component.java:4460)at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)这种错误到底指什么啊？我看不明白，都不知道咋改了。 问题补充：pwc_pengwenchao 写道
解决方案
Hello.BeatBox.buildTrackAndStart(BeatBox.java:92) 这不说了吗？ BeatBox.buildTrackAndStart(BeatBox.java:92) 这个方法的92行有null指针而引发的内存错误。