Python Notes for mca i year students osmania university.docx
Programming in Java
1. JAVA BUZZWORDS
(Features)
The most striking feature of the language is that it is PLATFORM-
NEUTRAL language.
Is the FIRST programming language that is not tied to any particular
hardware or OS.
JAVA programs can be executed anywhere on any system.
BUZZWORDS.
Compiled & Interpreted Multi-Threaded
Platform-Independent & Portable Object-Oriented
Simple High Performance
Safe (Secure) & Robust Dynamically Linked
Garbage Collected. Distributed
3. JAVA ENVIRONMENT
JAVA ENVIRONMENT
DEVELOPMENT TOOLS CLASSES AND METHODS.
Are part of JSL (Java Standard
are part of the system known as JDK
Library), also known as API
(Java Development Kit).
(Application Programming Interface)
Collection of tools used for developing and
running JAVA programs
4. JAVA DEVELOPMENT KIT
java –This tool is an interpreter and can interpret the
class files generated by the javac compiler
javac – the compiler, which converts source code into
Java bytecode
javadoc – the documentation generator, which
automatically generates documentation from source code
jdb – the debugger
javap – the class file disassembler
appletviewer– this tool can be used to run and debug
Java applets without a web browser
5. EXECUTION STEPS IN JAVA
To create a program in JAVA, we need to create a source code file
using a text editor.
The source code is then compiled using the JAVA COMPLIER javac
And then the program is executed using JAVA interpreter java.
TEXT EDITOR Compile
source code
into bytecode
JAVA SOURCE JAVA PROGRAM
CODE OUTPUT
INTERPRETER
javac
JAVA CLASS
java
FILE
6. HOW TO WRITE
A
JAVA PROGRAM?????
C++ program JAVA Program
class First
{
void main() public static void main( String args[])
{ {
cout<< “ My first C++ System.out.println(“My first JAVA
program”; program”);
getch(); }
} }
Since, JAVA is a true OO Language,
Everything must be placed inside a class.
7. WHERE TO WRITE JAVA PROGRAM
TEXT EDITOR IS USED to write JAVA program
8. NEXT WHAT??????????
Save your program with file name same as class name.
Extension of the file is java (eg:- first.java)
9. NEXT WHAT??????????
Compile your program using javac compiler.
For that go to DOS prompt;
Go to drive where your java file is stored
14. EXPLANATION OF PROGRAM
public Is an ACCESS SPECIFIER that declares
main as unprotected & thus is accessible to
all classes
static Declares the method as one that belongs to
entire class
void Means main does not returns value
args Contains an array of objects of the class
type String
System.out.println is similar to “cout” of C++
println Is a method and it is a
member of out object
out Is a static data member
of System class.
System Is a class
15. MORE ON BASICS OF JAVA
OUTOUT STATEMENTS:
println(name);
prints out what is stored in name, then goes to a new line
print(name);
prints out what is stored in name, but does not start a new line
print("My name is " + name);
put text in quotes
use + to print more than one item.
COMMENTS:
JAVA permits both single-line and multi-line comments.
Single-line comments starts with //
Multi-line comments starts with /* and ends with */
16. MORE ON BASICS OF JAVA
Every JAVA statement must end with a semicolon.
JAVA is case-sensitive.
Thus, Main is different from main in JAVA.
CASCADING IN JAVA
+ is used to print more than one item.
E.g.:-
System.out.println(“GOOD MORNING”);
System.out.println(“FE6”);
System.out.println(“CP II Lecture”);
OR
System.out.println(“GOOD MORNING”+”n FE6”+”t CP II Lecture”);