NullPointerException: Attempt to invoke interface method 'int java.lang.Comparable.compareTo(java.lang.Object)' on a null object reference

[sanpi-bobo]

05-14 11:30:54.272 29119 18266 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke interface method 'int java.lang.Comparable.compareTo(java.lang.Object)' on a null object reference
11005-14 11:30:54.272 29119 18266 E AndroidRuntime: at java.util.PriorityQueue.siftDownComparable(PriorityQueue.java:703)
11105-14 11:30:54.272 29119 18266 E AndroidRuntime: at java.util.PriorityQueue.siftDown(PriorityQueue.java:689)
11205-14 11:30:54.272 29119 18266 E AndroidRuntime: at java.util.PriorityQueue.removeAt(PriorityQueue.java:621)
11305-14 11:30:54.272 29119 18266 E AndroidRuntime: at java.util.PriorityQueue.remove(PriorityQueue.java:378)
11405-14 11:30:54.272 29119 18266 E AndroidRuntime: at com.xujiaji.dmlib2.widget.Controller.addToDisplay(Controller.java:348)
11505-14 11:30:54.272 29119 18266 E AndroidRuntime: at com.xujiaji.dmlib2.widget.Controller.addDMInQueue(Controller.java:331)
11605-14 11:30:54.272 29119 18266 E AndroidRuntime: at com.xujiaji.dmlib2.widget.Controller.runTask(Controller.java:115)
11705-14 11:30:54.272 29119 18266 E AndroidRuntime: at com.xujiaji.dmlib2.widget.Controller.run(Controller.java:102)
11805-14 11:30:54.272 29119 18266 E AndroidRuntime: at java.lang.Thread.run(Thread.java:764)
11905-14 11:30:54.274 29119 18266 E CrashHandler: In thread: Thread[Thread-372,5,main]
12005-14 11:30:54.274 29119 18266 E CrashHandler: UncaughtException detected: java.lang.NullPointerException: Attempt to invoke interface method 'int java.lang.Comparable.compareTo(java.lang.Object)' on a null object reference
12105-14 11:30:54.274 29119 18266 E CrashHandler: at java.util.PriorityQueue.siftDownComparable(PriorityQueue.java:703)
12205-14 11:30:54.274 29119 18266 E CrashHandler: at java.util.PriorityQueue.siftDown(PriorityQueue.java:689)
12305-14 11:30:54.274 29119 18266 E CrashHandler: at java.util.PriorityQueue.removeAt(PriorityQueue.java:621)
12405-14 11:30:54.274 29119 18266 E CrashHandler: at java.util.PriorityQueue.remove(PriorityQueue.java:378)
12505-14 11:30:54.274 29119 18266 E CrashHandler: at com.xujiaji.dmlib2.widget.Controller.addToDisplay(Controller.java:348)
12605-14 11:30:54.274 29119 18266 E CrashHandler: at com.xujiaji.dmlib2.widget.Controller.addDMInQueue(Controller.java:331)
12705-14 11:30:54.274 29119 18266 E CrashHandler: at com.xujiaji.dmlib2.widget.Controller.runTask(Controller.java:115)
12805-14 11:30:54.274 29119 18266 E CrashHandler: at com.xujiaji.dmlib2.widget.Controller.run(Controller.java:102)
12905-14 11:30:54.274 29119 18266 E CrashHandler: at java.lang.Thread.run(Thread.java:764)