There is no such parameter indicate the lib loading order in JVM (I believe), however, the java -classpath option itself will determine the class loading order base on the paths you put.
JDK document explain this: http://docs.oracle.com/javase/1.4.2/docs/tooldocs/windows/classpath.html
Specification order
The order in which you specify multiple class path entries is important. The Java interpreter will look for classes in the directories in the order they appear in the class path variable. In the example above, the Java interpreter will first look for a needed class in the directory C:\java\MyClasses. Only if it doesn't find a class with the proper name in that directory will the interpreter look in the C:\java\OtherClasses directory.