Android course session 1 ( intoduction to java )
- 1. ANDROID COURSE WITH JAVA Developed by Keroles Magdy keroles.m.yacoub@gmail.com 2019 ©
- 2. Welcome !
- 4. Difference of this course • Best practice for each topic. • Simple project in every session. • Problem solving. • Latest technology.
- 5. Session topics :- • Binary system & Machine language. • Meaning of programing. • What is java?. • JDK, JRE and JVM. • Tools & Setups. • Interpreter & Compiler. • Hello java program. • Data Types & Variables. • Keywords & Comments. • Operators.
- 6. Binary system & Machine language:- • Binary system uses only two symbols: typically "0" (zero) and "1" (one). • "binary" comes from "Bi-" meaning two, like "bi-" in words such as "bicycle" (two wheels) or "binocular" (two eyes). • Machine language is the only language a computer is capable of understanding. • 01001000 01100101 01101100 01101100 01101111 00100000 01010111 01101111 01110010 01101100 01100100 Hello World
- 7. Meaning of programing :- • process of designing and building an executable computer program Problem Definition Problem Analysis Coding & Documentation Testing & Debugging Maintenance
- 8. What is java? :- • Java is a programming language first released by Sun Microsystems in 1995. Java is fast, secure, and reliable. From laptops to datacenters, game consoles to scientific supercomputers, cell phones to the Internet. Java is everywhere!
- 9. JDK, JRE and JVM :- + + JDK Dev Tools JRE + Lib Files JVM
- 10. JDK, JRE and JVM :- • JDK, ( Java Development Kit ) provides environment to develop and run the Java programs. • Note : JDK is only used by Java Developers. • JRE, (Java Runtime Environment) is an environment to run program which are already developed. • JVM, (Java Virtual machine) is responsible for executing the java program line by line hence it is also known as interpreter.
- 11. Tools & Setups :- • https://www.oracle.com/technetwork/java/javase/downloads/jdk13- downloads-5672538.html • https://www-eu.apache.org/dist/netbeans/netbeans/11.1/Apache- NetBeans-11.1-bin-windows-x64.exe
- 12. Interpreter & Compiler :- • Interpreter, is a computer program, which coverts each high-level program statement into the machine code. • Convert code into machine code when the program is run. InterpreterSource Code Output
- 13. Interpreter & Compiler :- • Compile, will convert the code into machine code (create an exe) before program run. • Cannot fix errors found in that program. CompilerSource Code OutputMachine Code
- 14. Break
- 15. Hello java program :- • Code : • Output : • Hello, World!
- 16. Hello java program :- • Package, group of classes. • Class, consist of method and variable. • Function, a set of instructions that perform a task. • Method, a set of instructions that are associated with an object.
- 17. Data Types & Variables :- • Primitive datatypes, are predefined by the language and named by a keyword. • EX : ( boolean, char, byte, short, int, long, float and double ). • Non- Primitive datatypes, (Reference Datatypes) created using defined constructors of the classes. • EX : ( Classes, Arrays and String ).
- 18. Data Types & Variables :- • Size in memory. Data Type Default size boolean 1 bit char 2 byte byte 1 byte short 2 byte int 4 byte long 8 byte float 4 byte double 8 byte
- 19. Data Types & Variables :- • In java syntax boolean myBool = true; // true or false byte a = 68; // -128 to 127 short myNum = 5000; // -32768 to 32767 int myNum = 5; // -2147483648 to 2147483647 long myNum = 15000000000L; // -9223372036854775808 float myNum = 5.75f; // 3.4e−038 to 3.4e+038 double myNum = 19.99d; // 1.7e−308 to 1.7e+308 char a = ‘A’; String myText = "Hello";
- 20. Data Types & Variables :- • Variables, is a container which holds the value while the java program is executed. • Types : (local variable - instance variable - static variable ). • Local Variable, A variable declared inside the body of the method. • Instance Variable, A variable declared inside the class but outside the body of the method. • Static variable, share among all the instances of the class. Memory allocation for static variable happens only once when the class is loaded in the memory.
- 21. Keywords & Comments :- • Keywords, are also known as (reserved words). They are particular words which acts as a key to a code • EX : ( abstract-boolean-break-class-return ) • Comments, are statements that are not executed by the compiler and interpreter. Used to explanation about the variable, method, class • Types : 1) Java Single Line Comment ( // ) 2) Java Multi Line Comment ( /**/ ) 3) Java Documentation Comment ( /***/ )
- 22. Operators :- • Unary Operator. ( postfix, prefix ) • Arithmetic Operator. ( *, / ,% , +, -) • Relational Operator. ( <, >, <=, >=, ==, !=, instanceof ) • Logical Operator. ( &&, ||) • Ternary Operator. • Assignment Operator. ( =, +=, -=, *=, /=, %=)
- 23. the End