For Grade 9 Students

2. Java is a programming language created by
James Gosling from Sun Microsystem (Sun)
in 1991. The first publicy available version
of Java (Java 1.0) was released in 1995.
Sun microsystems was acquired by the
Oracle Corporation in 2010. Oracle has
now the steermanship for Java.

3. Java is a high-level language and software-only platform. It
runs on more than 50 million personal computers and on
billions of devices worldwide. 9 million developers have
created Java applications in all major industries.
Java also allows you to play online games, chat with people
around the world, calculate your mortgage interest, and
view images in 3D, just to name a few. It's also integral to
the intranet applications and other e-business solutions
that are the foundation of corporate computing.

4. Trying to design a very basic
chat room in JAVA RMI. My
design brief is that all clients
messages should be displayed to
other clients and also captured
and displayed on the server. I
have been able to get as far as
getting all client messages to
display on the server side, but I
am having difficulty in being
able to display the messages
sent by clients to other clients. I
have constructed a GUI for
clients in netbeans for them to
type and receive text. Does
anyone know of any ways I can
go about solving this issue?

5. The Java programming language is a high-level language that
can be characterized by all of the following buzzwords:
• Architecture neutral
•Portable
•High performance
•Robust
•Secure
•Object oriented
•Distributed
•Simple
•Multithreaded
•Dynamic
In the Java programming language, all source code is first
written in plain text files ending with
the .java extension. Those source files are then compiled
into .class files by the javac compiler. A .class file does
not contain code that is native to your processor; it
instead contains bytecodes — the machine language of the
Java Virtual Machine (Java VM). The java launcher tool then
runs your application with an instance of the Java Virtual
Machine.

6. JAVA LANGUAGE

7. OR

9. The two main components of
the Java platform are the Java
Application Programming
Interface (API), which is a
library of Java command lines
and the Java Virtual Machine
(JVM) that interprets Java

10. A platform is the hardware or
software environment in
which a program runs. We've
already mentioned some of
the most popular platforms
like Microsoft Windows,
Linux, Solaris OS, and Mac
OS. Most platforms can be
described as a combination
of the operating system and
underlying hardware. The
Java platform differs from
most other platforms in that
it's a software-only platform
that runs on top of other
hardware-based platforms.

11. You've already been introduced to the Java
Virtual Machine; it's the base for the Java
platform and is ported onto various hardware-
based platforms.
The API is a large collection of ready-made
software components that provide many useful
capabilities. It is grouped into libraries of related
classes and interfaces; these libraries are known
as packages.
As a platform-independent
environment, the Java
platform can be a bit slower
than native code. However,
advances in compiler and
virtual machine technologies
are bringing performance
close to that of native code
without threatening portability.

12. 10 REASONS WHY JAVA
ROCKS MORE THAN EVER
Part 1: The Java Compilerr
The compiler is one of the things we take
for granted in any language, without
thinking about its great features. In Java,
unlike C++, you can simply compile your
code without thinking too much about
linking, optimisation and all sorts of other
usual compiler features. This is partially
due to the JIT (Just In Time compiler),
which does further compilation work at
runtime. Part 2: The Core API
The JDK’s core API consists of a very
solid, stable and well-understood set of
libraries. While many people complain
about the lack of functionality in this area
(resorting to Google Guava or Apache
Commonss, people often forget that the
core API is still the one that is underneath
all those extensions. Again, from a C++
perspective, this is a truly luxurious
situation.

13. Part 3: Open Source
In this section, ZeroTurnaround’s
Geert Bevin‘s mind-set aligns well
with our own at Data Geekery when
it comes to the spirit of Open
Source – no matter whether this is
about free-as-in-freedom, or free-as-
in-beer, the point is that so many
things about Java are “open”. We’re
all in this together.
Part 4: The Java Memory Model
Again, a very interesting point of
view from someone with a solid C++
background. We’re taking many
things for granted as Java has had a
very good threading and memory
model from the beginning, which
was corrected only once in the JDK
1.5 in 2004, and which has built a
solid grounds for newer API like
actor-based ones, Fork/JOIN, etc.

14. Part 5: High-Performance
JVM
The JVM is the most obvious
thing to talk about it has
allowed for so many
languages to work on so
many hardware
environments, and it runs so
fast, nowadays!
Part 6: Bytecode
Bytecode is a vendor-independent
abstraction of machine code, which
is very predi ctable and can be
generated, manipulated, and
transformed by various
technologies. We’ve recently had a
guest post by Dr. Ming-Yee Iu who
has shown how bytecode
transformations can be used to
emulate LINQ in Java. Let’s hear it

15. Part 7: Intelligent IDEs
15 years ago, developing software worked quite
differently. People can write assembler or C programs
with vi or Notepad. But when you’re writing a very
complex enterprise-scale Java program, you wouldn’t
want to miss IDEs, nowadays. We’ve blogged
about various reasons why SQLJ has died. The lack of
proper IDE support was one of them.
Part 8: Profiling Tools
Remember when Oracle released Java Mission
Control for free developer use with the JDK
7u40? Profiling is something very very
awesome. With modern profilers, you can
know exactly where your bottleneck is by simply
measuring every aspect of your JVM. You don’t
have to guess, you can know.

16. Part 9: Backwards Compatibility
While backwards-compatibility has
its drawbacks, too, it is still
very impressive how long the Java
language, the JVM, and the JDK have
existed so far without introducing
any major backwards-compatibility
regressions. The only thing that
comes to mind is the introduction
of keywords like assert and enum.
Part 10: Maturity With Innovation
In fact, this article is a summary of all
the others, saying that Java has been a
very well-designed and mature
platform from the beginning without
ever ceasing to innovate. And it’s true.
With Java 8, a great next step has been
published that will – again – change
the way the enterprise perceives
software development for good.

17. HOW TO WRITE YOUR
FIRST PROGRAM IN JAVA
InordertostartwritingprogramsinJava,setupyour
workenvironment.ManyprogrammersuseIntegrated
DevelopmentEnvironments(IDEs)suchasEclipseand
NetbeansfortheirJavaprogramming,butonecanwrite
aJavaprogramandcompileitwithoutbloatedIDEs.
Any sort of Notepad-like program will
suffice for programming in Java.Hardcore
programmers sometimes prefer to use
text editors that are within the terminal
such as vim and emacs. A very good text
editor that can be installed on both a
Windows machine and on a linux-based
machine (Mac, Ubuntu, etc.) is Sublime
Text, which is what we will be using in
this tutorial.
Make sure that you
have the Java Software
Development
KIT installed. You will
need this for compiling
your program.
We will first create a program that prints
"Hello World." In your text editor, create
a new file and save it as
"HelloWorld.java". HelloWorld is your
class name and you will need your class
name to be the same name as your file.
Declare your class and your main
method. The main method public
static void main(String[] args) is the
method that will be executed when
the programming is running.
Write the line of
code that will
print out "Hello
World."
Put it all
together
Save your file and open
up command prompt or
terminal to compile the
program
Run the
program.
Congratulations,
you have made
your first Java
program!

18. MATTHEW CALIFF CALIP
MARIFER ABAO
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