May 2001
Intermediate to advanced
618 pages
20h 50m
English
Content preview from Java Security, 2nd EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Comparison with Previous Releases
In Java 2, version 1.3, no class loader
can define a class that is in the java
package (i.e., whose class name begins with
java). In 1.2 and earlier releases, that
restriction is not present (unless you code it into your own class
loader). That’s one reason why there is no class loader that
uses the checkPackageDefinition( ) method
(although that method was not used in 1.2 either).
In Java 1.1, class loading was significantly different. To begin, there are no code source or protection domain objects in 1.1, and classes do not carry associated permissions with them. Security in 1.1 is solely up to the security manager, and the class loader simply loads classes.
That means that the loadClass( )
method
in 1.1 is very different. In particular, there is only one
defineClass( )
method
that it can call (the one without a protection domain argument), and
it does not call the findClass( ) method. In
order to write a class loader in 1.1, you must override the
loadClass( ) method and perform all your work in
that method. We show an example of this in Appendix D.
The secure class loader and URL class loader were introduced in Java 2, version 1.2. In 1.1, the primordial class loader is used to load all classes on the classpath in addition to the classes in the core API.
Delegation was also introduced in Java 2, version 1.2. In 1.1, a custom class loader can make a special method call to load classes from the classpath, but there is no general hierarchy of ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.