The program violates secure coding principles for mobile code by making use of an inner class.
Inner classes quietly introduce serveral security concerns because of the way they are translated into Java bytecode. In Java source code, it appears that an inner class can be declared to be accessible only by the enclosing class, but Java bytecode has no concept of an inner class, so the compiler must transform an inner class declaration into a peer class with package
level access to the original outer class. More insidiously, since an inner class can access private
fields in their enclosing class, once an inner class becomes a peer class in bytecode, the compiler converts private
fields accessed by the inner class into protected
fields.
Example 1: The following Java Applet code mistakenly makes use of an inner class.
public final class urlTool extends Applet {
private final class urlHelper {
...
}
...
}
[1] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 492
[2] G. McGraw Securing Java. Chapter 7: Java Security Guidelines