netbeans - System.getProperty("java.classpath") = null? -

Hi guys, I wander around here and I need you to help me.

I posted it:

After some time, I decided to make a decision that it can not compile any report in iReport 5.6.0 .

This console in NetBeans:

  System.out.println (System.getProperty ("java.classpath"));  

I get blank

In this case, the Windows of the Java code version is incorrect?

What can I do? Nobody can help me.

property name is incorrect, this is java.class.path

  System.out.println (System.getProperty ("java.class.path"));