Java Interview Questions

Server is untrusted

Stubs could be malicious

rmic is OK, but someone could custom-code an evil stub: it’s just a .class file

RMI Security Managers

AppletSecurityManager

stub can only do what an applet can do

RMISecurityManager

disables all functions except class definition and access

A downloaded class is allowed to make a connection if the connection was initiated via the RMI transport.

None

Stub loading disabled

Stubs still work if they are in local classpath

writes object as a sequence of bytes

writes it to a Stream

recreates it on the other end

creates a brand new object with the old data

java.io.Serializable

Objects that implement the java.io.Serializable interface are marked as serializable

Also subclasses

Magically, all non-static and non-transient data members will be serialized

Actually, it’s not magic, it’s Reflection (it’s done with mirrors)

empty interface - just a marker

It’s a promise

Not All Objects Are Serializable

Any object that doesn’t implement Serializable

Any object that would pose a security risk

e.g. FileInputStream

Any object whose value depends on VM-specific information

e.g. Thread

Any object that contains a (non-static, non-transient) unserializable object (recursively)

NotSerializableException

thrown if you try to serialize or unserialize an unserializable object
maybe you subclassed a Serializable object and added some unserializable members

Primitive types

passed by value

Remote objects

passed by reference

Non-remote objects

passed by value