Beginning Java 01
Who made Java ?
James Gosling, Mike Sheridan and Patrick Naughton started to create the Java language project in June 1991.
Why created Java language project ?
Java was originally designed for interactive television, but seems it is "Over Qualified", it is too advance for television industry at the time. Gosling aimed to implement a virtual machine and a language that had a familiar C/C++ style of notation.
Why named Java ?
Java was not called Java originally, it was Oak since there was an Oak tree was outside of James Gosling’ office. Later Oak changed to Green, finally named to Java from a list of random words. So we know the name Java was just from a choose randomly.
When the first Java version released ?
Sun Microsystems released the first public implementation as Java 1.0 in 1995. James Gosling was working for them at that time.
What is J2EE, J2ME, J2SE, Java EE, Java ME, Java SE ?
Simply, J2EE targeted enterprise applications, J2ME is for mobile applications (Mobile Java). J2SE designated the Standard Edition. In 2006, for marketing purposes, Sun renamed new J2 versions as Java EE, Java ME, and Java SE, respectively.
Java Icon ?
Java supports C++ style pointers?
Like C# (Actually C# learn from Java, but Java originally learn lots of stuff from C++), Java does not support C/C++ style pointer arithmetic.
Default file extension name?
A suffix .java
"main" is NOT a keyword in Java.
The method name "main" is not a keyword in the Java language (Actually in C#, "main" is not a keyword either, but normally in C# we use Main (capital) for a method name). Java classes that run in managed environments such as applets and Enterprise JavaBean do not use or need a main() method. A java program may contain multiple classes that have main methods, which means that the VM needs to be explicitly told which class to launch from.
What is JRE?
JRE is Java Runtime Environment. End-users use a Java Runtime Environment (JRE) installed on their own machine for standalone Java applications, or in a Web browser for Java applets.
What is JDK?
JDK is Java Development Kit. Sun distributes a superset of the JRE called JDK, which includes development tools such as the Java compiler, Javadoc, Jar, and debugger.
Java Target platforms.
Sun defined four editions of Java targeting platforms:
Java Card — which is for smartcards.
Java ME — Java Platform, Micro Edition, targeting environments with limited resources.
Java SE — Java Platform, Standard Edition, targeting workstation environments.
Java EE — Java Platform, Enterprise Edition, targeting large distributed enterprise or Internet environments.