[plutonas@myhost java]$ javac -encoding ISO-8859-1 lu/cs/co/graph/*.java
lu/cs/co/graph/Book.java:182: cannot access java.util.PriorityQueue
bad class file: /home/plutonas/java/java/util/PriorityQueue.java
file does not contain class java.util.PriorityQueue
Please remove or make sure it appears in the correct subdirectory of the classpath.
      PriorityQueue P= new PriorityQueue(characters);
      ^
Note: lu/cs/co/graph/Graph.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error
[plutonas@myhost java]$ java lu.cs.co.Graph m 3
Exception in thread "main" java.lang.NoClassDefFoundError: lu/cs/co/Graph