implementation of isCurrentlyRunning(int taskId);

Burrows down to the worker thread assigned to this task, and returns
its alive status. If no such thread exists, then the task is not
running!

src/main/java/org/bukkit/craftbukkit/scheduler/CraftTask.java

@@ -4,7 +4,7 @@ import java.lang.Comparable;
 
 import org.bukkit.plugin.Plugin;
 
-public class CraftTask implements Comparable {
+public class CraftTask implements Comparable<Object> {
 
     private final Runnable task;
     private final boolean syncTask;